Question

in which interval of f(x)=cos(x) is the inverse also a function?

Answer 1

@satellite73 plz help

Answer 2

for this one the commonly used restriction is \([0,\pi]\) as on that interval cosine is strictly decreasing

Answer 3

but how do u no this?

Answer 4

here is a picture of cosine restricted to that domain

Answer 5

because i know what cosine looks like in general
http://www.wolframalpha.com/input/?i=cos%28x%29

Answer 6

but y do chose (0,pi)

Answer 7

that is the picture of cosine
here is the picture of the restricted cosine
http://www.wolframalpha.com/input/?i=cos%28x%29+domain+0..pi

Answer 8

that particular interval is chosen by convention
you could choose another one, say \([\pi.2\pi]\)

Answer 9

I dnt gt how these pics help u identify the answers?

Answer 10

here is my lousy picture of cosine
not one to one for sure

Answer 11

erase most of it, then it is one to one