Funkcija je kot matematični stroj - vstaviš število, dobiš rezultat... Show more
Matematika
Angleščina
Naravoslovje
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Updated May 12, 2026
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Osnovno razumevanje funkcij
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Kaj je funkcija?
Predstavljaj si funkcijo kot pametno napravo, ki deluje po jasnem pravilu. Vstaviš neko število (recimo 3), ona ga predela in ti da natančno določen rezultat. Ključno je, da za vsak vhod dobiš natanko en izhod - to je osnovno pravilo funkcij.
Te matematične stroje srečuješ povsod: pri računanju hitrosti glede na čas, pri določanju cene glede na količino blaga, ali pri spreminjanju temperature čez dan. Neodvisna spremenljivka (običajno x) je tisto, kar sam izbereš, odvisna spremenljivka (y) pa je rezultat, ki ga dobiš.
Definicijsko območje (Df) so vsi dovoljeni vhodi, zaloga vrednosti (Zf) pa vsi možni rezultati. Zapomni si: če bi en x dal dva različna y-a, to sploh ne bi bila funkcija!
💡 Nasvet: Funkcijo prepoznaš tako, da za vsak x obstaja točno en y. To je železno pravilo!
Kako predstaviš funkcijo?
Funkcijo lahko prikažeš na štiri načine, ki vsi opisujejo isto stvar. Funkcijski predpis (formula) je najpogostejši - recimo f(x) = 2x + 1. To ti pove, kaj moraš z x-om narediti, da dobiš y.
Vrednostna tabela je super, ko hočeš narisati graf. Vzameš nekaj vrednosti za x, jih vstaviš v formulo in izračunaš pripadajoče y-e. Tako za f(x) = 2x + 1 dobiš pare kot (-1, -1), (0, 1), (1, 3).
Graf je slikovni prikaz v koordinatnem sistemu - x-i gredo na vodoravno os, y-i na navpično. Vsaka točka predstavlja par (x, y). Urejeni pari so pa samo drugačen zapis tabele v oklepajih.
💡 Nasvet: Vsi štirje načini prikazujejo isto funkcijo, le da drugače. Izberi tistega, ki ti v dani situaciji najbolj ustreza!
Linearna funkcija - primer
Vzemimo funkcijo f(x) = x - 2, kjer je definicijsko območje vsa realna števila. To pomeni, da lahko za x vzameš katero koli število.
Če hočeš izračunati vrednosti, preprosto vstaviš število v formulo. Za x = 4 dobiš f(4) = 4 - 2 = 2, za x = 0 je f(0) = 0 - 2 = -2, za x = -1 pa f(-1) = -1 - 2 = -3.
V tabeli bi to izgledalo takole: (-1, -3), (0, -2), (4, 2). Če bi te točke narisal na koordinatno mrežo, bi bile vse na isti premici - zato se taki funkciji reče linearna funkcija.
💡 Nasvet: Pri linearnih funkcijah graf vedno dobi premico. Dovolj ti je izračunati samo dve točki!
Kvadratna funkcija in test funkcije
Funkcija g(x) = x² je kvadratna funkcija. Tudi tu za vsak x dobiš natanko en rezultat: g(-2) = 4, g(-1) = 1, g(0) = 0, g(1) = 1, g(2) = 4.
Opazi, da lahko različna x-a dajo isti y . To je popolnoma v redu! Pomembno je le, da en x ne da dveh različnih y-jev.
Za preverjanje, ali je graf funkcija, uporabi test z navpično premico. Če navpična črta graf seka največ enkrat, je to funkcija. Če ga seka večkrat (kot pri krožnici), to ni funkcija.
💡 Nasvet: Test z navpično premico je tvoj najboljši prijatelj za preverjanje funkcij. Deluje vedno!
Hitro ponavljanje za test
Za teste si zapomni osnove: funkcija je pravilo, ki x-u priredi točno en y. Domena (Df) so vsi možni x-i, zaloga vrednosti (Zf) pa vsi možni y-i.
Funkcijo lahko podaš s predpisom , tabelo, grafom ali urejenimi pari. Vse te načine moraš obvladati in znati pretvarjati enega v drugega.
Ne pozabi: x je neodvisna spremenljivka (ti jo izbiraš), y je odvisna (rezultat). Zapis f(x) je samo drugo ime za y, torej velja y = f(x).
💡 Nasvet: Na testu si najprej preveri, ali res velja osnovno pravilo - en x, en y. Potem lahko mirno rešuješ naprej!
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4.6/5
App Store
4.7/5
Google 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 S
iOS 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 Klich
Android 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.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE Knowunity AI. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
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 S
iOS 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 Klich
Android 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.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE Knowunity AI. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
Osnovno razumevanje funkcij
Funkcija je kot matematični stroj - vstaviš število, dobiš rezultat po določenem pravilu. To je eden najpomembnejših konceptov v matematiki, ki ga srečuješ povsod okrog sebe.
Kaj je funkcija?
Predstavljaj si funkcijo kot pametno napravo, ki deluje po jasnem pravilu. Vstaviš neko število (recimo 3), ona ga predela in ti da natančno določen rezultat. Ključno je, da za vsak vhod dobiš natanko en izhod - to je osnovno pravilo funkcij.
Te matematične stroje srečuješ povsod: pri računanju hitrosti glede na čas, pri določanju cene glede na količino blaga, ali pri spreminjanju temperature čez dan. Neodvisna spremenljivka (običajno x) je tisto, kar sam izbereš, odvisna spremenljivka (y) pa je rezultat, ki ga dobiš.
Definicijsko območje (Df) so vsi dovoljeni vhodi, zaloga vrednosti (Zf) pa vsi možni rezultati. Zapomni si: če bi en x dal dva različna y-a, to sploh ne bi bila funkcija!
💡 Nasvet: Funkcijo prepoznaš tako, da za vsak x obstaja točno en y. To je železno pravilo!
Sign up to see the contentIt's free!
Access to all documents
Improve your grades
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Kako predstaviš funkcijo?
Funkcijo lahko prikažeš na štiri načine, ki vsi opisujejo isto stvar. Funkcijski predpis (formula) je najpogostejši - recimo f(x) = 2x + 1. To ti pove, kaj moraš z x-om narediti, da dobiš y.
Vrednostna tabela je super, ko hočeš narisati graf. Vzameš nekaj vrednosti za x, jih vstaviš v formulo in izračunaš pripadajoče y-e. Tako za f(x) = 2x + 1 dobiš pare kot (-1, -1), (0, 1), (1, 3).
Graf je slikovni prikaz v koordinatnem sistemu - x-i gredo na vodoravno os, y-i na navpično. Vsaka točka predstavlja par (x, y). Urejeni pari so pa samo drugačen zapis tabele v oklepajih.
💡 Nasvet: Vsi štirje načini prikazujejo isto funkcijo, le da drugače. Izberi tistega, ki ti v dani situaciji najbolj ustreza!
Sign up to see the contentIt's free!
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Linearna funkcija - primer
Vzemimo funkcijo f(x) = x - 2, kjer je definicijsko območje vsa realna števila. To pomeni, da lahko za x vzameš katero koli število.
Če hočeš izračunati vrednosti, preprosto vstaviš število v formulo. Za x = 4 dobiš f(4) = 4 - 2 = 2, za x = 0 je f(0) = 0 - 2 = -2, za x = -1 pa f(-1) = -1 - 2 = -3.
V tabeli bi to izgledalo takole: (-1, -3), (0, -2), (4, 2). Če bi te točke narisal na koordinatno mrežo, bi bile vse na isti premici - zato se taki funkciji reče linearna funkcija.
💡 Nasvet: Pri linearnih funkcijah graf vedno dobi premico. Dovolj ti je izračunati samo dve točki!
Sign up to see the contentIt's free!
Access to all documents
Improve your grades
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Kvadratna funkcija in test funkcije
Funkcija g(x) = x² je kvadratna funkcija. Tudi tu za vsak x dobiš natanko en rezultat: g(-2) = 4, g(-1) = 1, g(0) = 0, g(1) = 1, g(2) = 4.
Opazi, da lahko različna x-a dajo isti y . To je popolnoma v redu! Pomembno je le, da en x ne da dveh različnih y-jev.
Za preverjanje, ali je graf funkcija, uporabi test z navpično premico. Če navpična črta graf seka največ enkrat, je to funkcija. Če ga seka večkrat (kot pri krožnici), to ni funkcija.
💡 Nasvet: Test z navpično premico je tvoj najboljši prijatelj za preverjanje funkcij. Deluje vedno!
Sign up to see the contentIt's free!
Access to all documents
Improve your grades
Join milions of students
Hitro ponavljanje za test
Za teste si zapomni osnove: funkcija je pravilo, ki x-u priredi točno en y. Domena (Df) so vsi možni x-i, zaloga vrednosti (Zf) pa vsi možni y-i.
Funkcijo lahko podaš s predpisom , tabelo, grafom ali urejenimi pari. Vse te načine moraš obvladati in znati pretvarjati enega v drugega.
Ne pozabi: x je neodvisna spremenljivka (ti jo izbiraš), y je odvisna (rezultat). Zapis f(x) je samo drugo ime za y, torej velja y = f(x).
💡 Nasvet: Na testu si najprej preveri, ali res velja osnovno pravilo - en x, en y. Potem lahko mirno rešuješ naprej!
Sign up to see the contentIt's free!
Access to all documents
Improve your grades
Join milions of students
Sign up to see the contentIt's free!
Access to all documents
Improve your grades
Join milions of students
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.
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Students love us — and so will you.
4.6/5
App Store
4.7/5
Google 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 S
iOS 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 Klich
Android 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.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE Knowunity AI. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
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 S
iOS 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 Klich
Android 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.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE Knowunity AI. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user