Knowunity AI

Open the App

Subjects

MathsMaths356 views·Updated May 23, 2026·5 pages

Easy Trigonometry: Fun With Trigonometric Identities, Cosine Rule, and Quadratic Problems

user profile picture
Kate@katerevisionotes

A comprehensive guide to trigonometric identities and equations examples,... Show more

1
of 5
T
Trigonometry
• Trigommetry
sine =  opp
hypotenuse
hyp
Opposite
cose =  adj
Π
hyp
adjacent
tano =  opp
adj
θ = sin⁻¹(π)
θ = 605⁻¹(π)
θ = ta

Page 2: Advanced Trigonometric Functions

This page delves into transformations of trigonometric functions and essential identities.

Vocabulary: Cast diagrams are visual tools used to determine the signs of trigonometric ratios in different quadrants.

Definition: The fundamental trigonometric identity sin²θ + cos²θ = 1 forms the basis for many trigonometric proofs.

Example: When solving 2cosx = -1 in the range -180° ≤ x ≤ 540°, solutions are found at x = 120°, 240°

2
of 5
T
Trigonometry
• Trigommetry
sine =  opp
hypotenuse
hyp
Opposite
cose =  adj
Π
hyp
adjacent
tano =  opp
adj
θ = sin⁻¹(π)
θ = 605⁻¹(π)
θ = ta

Page 3: Complex Trigonometric Applications

This section covers advanced topics including quadratic trigonometry and compound angles.

Highlight: Quadratic trigonometry factorization problems can be solved by treating trigonometric equations as standard quadratic equations.

Definition: Compound angle formulae:

  • sinA+BA+B = sinA cosB + cosA sinB
  • cosA+BA+B = cosA cosB - sinA sinB

Example: The equation tan²x - 2tanx = 0 can be factored as tanxtanx2tanx - 2 = 0

3
of 5
T
Trigonometry
• Trigommetry
sine =  opp
hypotenuse
hyp
Opposite
cose =  adj
Π
hyp
adjacent
tano =  opp
adj
θ = sin⁻¹(π)
θ = 605⁻¹(π)
θ = ta

Page 4: Double Angle Formulae and R-Addition

This page explores double angle formulae and R-addition techniques.

Definition: Double angle formulae include:

  • sin(2A) = 2sinA cosA
  • cos(2A) = cos²A - sin²A

Example: For R-addition formula, 5cosx - 12sinx can be written as 13cosx+67.38°x + 67.38°

Highlight: The R-addition formula transforms expressions of the form asinx + bcosx into Rsinx+αx + α or Rcosx+αx + α

4
of 5
T
Trigonometry
• Trigommetry
sine =  opp
hypotenuse
hyp
Opposite
cose =  adj
Π
hyp
adjacent
tano =  opp
adj
θ = sin⁻¹(π)
θ = 605⁻¹(π)
θ = ta

Page 5: Advanced Trigonometric Proofs

The final page focuses on complex trigonometric proofs and properties.

Example: Proving relationships involving tangent and cotangent functions requires careful manipulation of basic identities.

Highlight: Advanced proofs often involve converting expressions to simpler forms using fundamental identities.

Definition: The relationship between tangent and cotangent functions is essential for solving complex trigonometric equations.

5
of 5
T
Trigonometry
• Trigommetry
sine =  opp
hypotenuse
hyp
Opposite
cose =  adj
Π
hyp
adjacent
tano =  opp
adj
θ = sin⁻¹(π)
θ = 605⁻¹(π)
θ = ta

Page 1: Fundamental Trigonometric Concepts

This page introduces the core concepts of trigonometry, focusing on basic ratios and rules for triangle calculations.

Definition: Trigonometric ratios are defined as relationships between sides of right-angled triangles:

  • sine = opposite/hypotenuse
  • cosine = adjacent/hypotenuse
  • tangent = opposite/adjacent

Highlight: The cosine rule a2=b2+c22bccosAa² = b² + c² - 2bc cosA is essential for solving non-right angled triangles with cosine rule.

Example: Trigonometric graphs show the periodic nature of functions, with sin curves ranging between -1 and 1.

We thought you’d never ask...

What is the Knowunity AI companion?

Our AI Companion is a student-focused AI tool that offers more than just answers. Built on millions of Knowunity resources, it provides relevant information, personalised study plans, quizzes, and content directly in the chat, adapting to your individual learning journey.

Where can I download the Knowunity app?

You can download the app from Google Play Store and Apple App Store.

Is Knowunity really free of charge?

That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.

Most popular content: Pythagorean Identities

1

Most popular content in Maths

9
MathsMaths

Comprehensive Maths Concepts

Explore essential mathematical concepts including powers, geometry, statistics, and probability. This resource features 65 pages of detailed explanations, diagrams, and examples to enhance your understanding of topics such as right triangles, volume calculations, and data representation. Ideal for students seeking to strengthen their numeracy skills and grasp complex mathematical principles.

1079,6336,315
MathsMaths

GCSE Maths (Higher) // Revision Guide

The only GCSE maths (higher) revision guide you need to get a grade 9! Contains every topic, each with all potential question types and their solutions.

102,14951
MathsMaths

Comprehensive Maths Concepts

Explore essential mathematical concepts including polynomial theorems, logarithmic properties, trigonometric functions, and integration techniques. This resource covers everything from solving inequalities to understanding exponential functions, providing a solid foundation for A-level mathematics. Ideal for students aiming for top grades.

1221,9561,816
M
MathsMaths

Medium Level alerbra

Master challenging maths concepts with this medium level flashcard set designed for grade 7/8 students. Strengthen your problem-solving skills and boost your confidence in maths!

74393
M
MathsMaths

Mastering Maths: Essential Concepts for Grade 10

Boost your math skills with this comprehensive flashcard set covering key concepts for grade 10. Perfect for exam preparation and building a strong foundation in mathematics.

103561
M
MathsMaths

Mastering Medium-Level Maths: Essential Flashcards for Grade 11 Students

Boost your Maths skills with this comprehensive set of flashcards designed specifically for Grade 11 students. Covering medium-level topics, these cards will help you ace your exams and build a solid foundation for advanced Maths.

118413
MathsMaths

Comprehensive Maths Concepts

Explore essential higher mathematics concepts including calculus, trigonometry, polynomials, and vector analysis. This summary covers key topics such as differentiation, integration, quadratic equations, and the properties of circles, providing a solid foundation for exam preparation. Ideal for students seeking a concise yet thorough review of advanced mathematical principles.

S51,93657
MathsMaths

AS Level Statistics Overview

Explore key concepts in AS Level Statistics, including hypothesis testing, binomial distribution, linear regression, and sampling methods. This summary covers essential statistical measures, significance levels, and data analysis techniques, providing a comprehensive guide for Year 1 applied maths students.

121,50861
P
MathsMaths

Percentage,fractions and decimals

how well do you know percentages,fractions and decimals

72453

Most popular content

9
SociologySociology

Sociology of Education Overview

Explore comprehensive A-Level Sociology notes on the education system, covering key theories, policies, and sociological perspectives. This resource includes insights on marketisation, gender roles, cultural deprivation, and educational inequalities, providing a thorough understanding of how education shapes social stratification and individual achievement. Ideal for exam preparation and in-depth study.

12101,9803,036
SociologySociology

Sociology of Families: Comprehensive Revision

Dive into an extensive overview of family dynamics, perspectives, and patterns in sociology. This resource covers key concepts such as family diversity, gender roles, marriage, and the impact of social policies on family structures. Perfect for A-Level Sociology students preparing for Paper 2.

1271,7822,285
CriminologyCriminology

Criminology: Crime & Punishment Overview

Comprehensive mindmaps covering key concepts in the Crime and Punishment topic for WJEC Criminology Unit 4. This resource includes detailed insights into the Criminal Justice System, crime prevention strategies, sentencing models, and the roles of various agencies. Ideal for A-Level revision, ensuring you grasp essential theories and legislative processes to excel in your exams.

1251,8941,028
English LiteratureEnglish Literature

An Inspector Calls: Character Insights

Explore in-depth analysis and key quotes for characters in J.B. Priestley's 'An Inspector Calls'. This resource covers Gerald Croft, Inspector Goole, Sheila Birling, Mrs. Birling, Eric Birling, and Eva Smith, focusing on themes of class, gender roles, and social responsibility. Ideal for students aiming for Grade 8 and above.

1025,056896
CriminologyCriminology

WJEC Unit 4 Criminology

Criminology unit 4 detailed revision note

126,427119
CriminologyCriminology

Criminology Theories Overview

Explore key criminology theories and their implications on crime and deviance. This comprehensive summary covers biological, psychological, and sociological perspectives, including labelling theory, right realism, and the impact of social campaigns on policy development. Ideal for A-Level criminology students seeking to understand the complexities of criminal behaviour and the factors influencing crime prevention strategies.

129,732211
English LiteratureEnglish Literature

Romeo and Juliet: Key themes

Key Romeo and Juliet themes and analysed quotes

106,565193
English LiteratureEnglish Literature

Macbeth: Guilt and Ambition

Explore the complex themes of guilt and ambition in Shakespeare's 'Macbeth'. This analysis covers key characters, including Macbeth and Lady Macbeth, their moral dilemmas, and the tragic consequences of their ambition. Ideal for students studying character motivations, thematic elements, and the psychological impact of power. Includes insights on the natural order, manipulation, and the descent into madness.

918,677387
C
BiologyBiology

Cell Biology and Cell structure

cell structures

92,4210

Can't find what you're looking for? Explore other subjects.

Students love us — and so will you.

4.6/5App Store
4.7/5Google Play

The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.

Stefan SiOS user

This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.

Samantha KlichAndroid user

Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.

AnnaiOS user

MathsMaths356 views·Updated May 23, 2026·5 pages

Easy Trigonometry: Fun With Trigonometric Identities, Cosine Rule, and Quadratic Problems

user profile picture
Kate@katerevisionotes

A comprehensive guide to trigonometric identities and equations examples, covering fundamental concepts and advanced applications in trigonometry.

  • Explores essential trigonometric ratios (sine, cosine, tangent) and their relationships in right-angled triangles
  • Details methods for solving non-right angled triangles with cosine... Show more

1
of 5
T
Trigonometry
• Trigommetry
sine =  opp
hypotenuse
hyp
Opposite
cose =  adj
Π
hyp
adjacent
tano =  opp
adj
θ = sin⁻¹(π)
θ = 605⁻¹(π)
θ = ta

Sign up to see the content. It's free!

  • Access to all documents
  • Improve your grades
  • Join milions of students

Page 2: Advanced Trigonometric Functions

This page delves into transformations of trigonometric functions and essential identities.

Vocabulary: Cast diagrams are visual tools used to determine the signs of trigonometric ratios in different quadrants.

Definition: The fundamental trigonometric identity sin²θ + cos²θ = 1 forms the basis for many trigonometric proofs.

Example: When solving 2cosx = -1 in the range -180° ≤ x ≤ 540°, solutions are found at x = 120°, 240°

2
of 5
T
Trigonometry
• Trigommetry
sine =  opp
hypotenuse
hyp
Opposite
cose =  adj
Π
hyp
adjacent
tano =  opp
adj
θ = sin⁻¹(π)
θ = 605⁻¹(π)
θ = ta

Sign up to see the content. It's free!

  • Access to all documents
  • Improve your grades
  • Join milions of students

Page 3: Complex Trigonometric Applications

This section covers advanced topics including quadratic trigonometry and compound angles.

Highlight: Quadratic trigonometry factorization problems can be solved by treating trigonometric equations as standard quadratic equations.

Definition: Compound angle formulae:

  • sinA+BA+B = sinA cosB + cosA sinB
  • cosA+BA+B = cosA cosB - sinA sinB

Example: The equation tan²x - 2tanx = 0 can be factored as tanxtanx2tanx - 2 = 0

3
of 5
T
Trigonometry
• Trigommetry
sine =  opp
hypotenuse
hyp
Opposite
cose =  adj
Π
hyp
adjacent
tano =  opp
adj
θ = sin⁻¹(π)
θ = 605⁻¹(π)
θ = ta

Sign up to see the content. It's free!

  • Access to all documents
  • Improve your grades
  • Join milions of students

Page 4: Double Angle Formulae and R-Addition

This page explores double angle formulae and R-addition techniques.

Definition: Double angle formulae include:

  • sin(2A) = 2sinA cosA
  • cos(2A) = cos²A - sin²A

Example: For R-addition formula, 5cosx - 12sinx can be written as 13cosx+67.38°x + 67.38°

Highlight: The R-addition formula transforms expressions of the form asinx + bcosx into Rsinx+αx + α or Rcosx+αx + α

4
of 5
T
Trigonometry
• Trigommetry
sine =  opp
hypotenuse
hyp
Opposite
cose =  adj
Π
hyp
adjacent
tano =  opp
adj
θ = sin⁻¹(π)
θ = 605⁻¹(π)
θ = ta

Sign up to see the content. It's free!

  • Access to all documents
  • Improve your grades
  • Join milions of students

Page 5: Advanced Trigonometric Proofs

The final page focuses on complex trigonometric proofs and properties.

Example: Proving relationships involving tangent and cotangent functions requires careful manipulation of basic identities.

Highlight: Advanced proofs often involve converting expressions to simpler forms using fundamental identities.

Definition: The relationship between tangent and cotangent functions is essential for solving complex trigonometric equations.

5
of 5
T
Trigonometry
• Trigommetry
sine =  opp
hypotenuse
hyp
Opposite
cose =  adj
Π
hyp
adjacent
tano =  opp
adj
θ = sin⁻¹(π)
θ = 605⁻¹(π)
θ = ta

Sign up to see the content. It's free!

  • Access to all documents
  • Improve your grades
  • Join milions of students

Page 1: Fundamental Trigonometric Concepts

This page introduces the core concepts of trigonometry, focusing on basic ratios and rules for triangle calculations.

Definition: Trigonometric ratios are defined as relationships between sides of right-angled triangles:

  • sine = opposite/hypotenuse
  • cosine = adjacent/hypotenuse
  • tangent = opposite/adjacent

Highlight: The cosine rule a2=b2+c22bccosAa² = b² + c² - 2bc cosA is essential for solving non-right angled triangles with cosine rule.

Example: Trigonometric graphs show the periodic nature of functions, with sin curves ranging between -1 and 1.

We thought you’d never ask...

What is the Knowunity AI companion?

Our AI Companion is a student-focused AI tool that offers more than just answers. Built on millions of Knowunity resources, it provides relevant information, personalised study plans, quizzes, and content directly in the chat, adapting to your individual learning journey.

Where can I download the Knowunity app?

You can download the app from Google Play Store and Apple App Store.

Is Knowunity really free of charge?

That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.

Most popular content: Pythagorean Identities

1

Most popular content in Maths

9
MathsMaths

Comprehensive Maths Concepts

Explore essential mathematical concepts including powers, geometry, statistics, and probability. This resource features 65 pages of detailed explanations, diagrams, and examples to enhance your understanding of topics such as right triangles, volume calculations, and data representation. Ideal for students seeking to strengthen their numeracy skills and grasp complex mathematical principles.

1079,6336,315
MathsMaths

GCSE Maths (Higher) // Revision Guide

The only GCSE maths (higher) revision guide you need to get a grade 9! Contains every topic, each with all potential question types and their solutions.

102,14951
MathsMaths

Comprehensive Maths Concepts

Explore essential mathematical concepts including polynomial theorems, logarithmic properties, trigonometric functions, and integration techniques. This resource covers everything from solving inequalities to understanding exponential functions, providing a solid foundation for A-level mathematics. Ideal for students aiming for top grades.

1221,9561,816
M
MathsMaths

Medium Level alerbra

Master challenging maths concepts with this medium level flashcard set designed for grade 7/8 students. Strengthen your problem-solving skills and boost your confidence in maths!

74393
M
MathsMaths

Mastering Maths: Essential Concepts for Grade 10

Boost your math skills with this comprehensive flashcard set covering key concepts for grade 10. Perfect for exam preparation and building a strong foundation in mathematics.

103561
M
MathsMaths

Mastering Medium-Level Maths: Essential Flashcards for Grade 11 Students

Boost your Maths skills with this comprehensive set of flashcards designed specifically for Grade 11 students. Covering medium-level topics, these cards will help you ace your exams and build a solid foundation for advanced Maths.

118413
MathsMaths

Comprehensive Maths Concepts

Explore essential higher mathematics concepts including calculus, trigonometry, polynomials, and vector analysis. This summary covers key topics such as differentiation, integration, quadratic equations, and the properties of circles, providing a solid foundation for exam preparation. Ideal for students seeking a concise yet thorough review of advanced mathematical principles.

S51,93657
MathsMaths

AS Level Statistics Overview

Explore key concepts in AS Level Statistics, including hypothesis testing, binomial distribution, linear regression, and sampling methods. This summary covers essential statistical measures, significance levels, and data analysis techniques, providing a comprehensive guide for Year 1 applied maths students.

121,50861
P
MathsMaths

Percentage,fractions and decimals

how well do you know percentages,fractions and decimals

72453

Most popular content

9
SociologySociology

Sociology of Education Overview

Explore comprehensive A-Level Sociology notes on the education system, covering key theories, policies, and sociological perspectives. This resource includes insights on marketisation, gender roles, cultural deprivation, and educational inequalities, providing a thorough understanding of how education shapes social stratification and individual achievement. Ideal for exam preparation and in-depth study.

12101,9803,036
SociologySociology

Sociology of Families: Comprehensive Revision

Dive into an extensive overview of family dynamics, perspectives, and patterns in sociology. This resource covers key concepts such as family diversity, gender roles, marriage, and the impact of social policies on family structures. Perfect for A-Level Sociology students preparing for Paper 2.

1271,7822,285
CriminologyCriminology

Criminology: Crime & Punishment Overview

Comprehensive mindmaps covering key concepts in the Crime and Punishment topic for WJEC Criminology Unit 4. This resource includes detailed insights into the Criminal Justice System, crime prevention strategies, sentencing models, and the roles of various agencies. Ideal for A-Level revision, ensuring you grasp essential theories and legislative processes to excel in your exams.

1251,8941,028
English LiteratureEnglish Literature

An Inspector Calls: Character Insights

Explore in-depth analysis and key quotes for characters in J.B. Priestley's 'An Inspector Calls'. This resource covers Gerald Croft, Inspector Goole, Sheila Birling, Mrs. Birling, Eric Birling, and Eva Smith, focusing on themes of class, gender roles, and social responsibility. Ideal for students aiming for Grade 8 and above.

1025,056896
CriminologyCriminology

WJEC Unit 4 Criminology

Criminology unit 4 detailed revision note

126,427119
CriminologyCriminology

Criminology Theories Overview

Explore key criminology theories and their implications on crime and deviance. This comprehensive summary covers biological, psychological, and sociological perspectives, including labelling theory, right realism, and the impact of social campaigns on policy development. Ideal for A-Level criminology students seeking to understand the complexities of criminal behaviour and the factors influencing crime prevention strategies.

129,732211
English LiteratureEnglish Literature

Romeo and Juliet: Key themes

Key Romeo and Juliet themes and analysed quotes

106,565193
English LiteratureEnglish Literature

Macbeth: Guilt and Ambition

Explore the complex themes of guilt and ambition in Shakespeare's 'Macbeth'. This analysis covers key characters, including Macbeth and Lady Macbeth, their moral dilemmas, and the tragic consequences of their ambition. Ideal for students studying character motivations, thematic elements, and the psychological impact of power. Includes insights on the natural order, manipulation, and the descent into madness.

918,677387
C
BiologyBiology

Cell Biology and Cell structure

cell structures

92,4210

Can't find what you're looking for? Explore other subjects.

Students love us — and so will you.

4.6/5App Store
4.7/5Google Play

The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.

Stefan SiOS user

This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.

Samantha KlichAndroid user

Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.

AnnaiOS user