What is the y-value for f(x) = cos(x) when x = -90°?

Question

anonymous · Answer

@demonchild99 @william.1233 @YGHOOTIE @dejmccray @haydenhd @Vendela

anonymous · Answer

51

anonymous · Answer

Put $x=-90$

anonymous · Answer

$$f(x) = \cos(-90^{\circ})$$

anonymous · Answer

And remember, cos(x) is an even function that means:
$$\cos(-x) = \cos(x)$$
It means negative angle just becomes positive..

anonymous · Answer

so the answere will be? :D

anonymous · Answer

$$f(x) = \cos(-90^{\circ}) \ f(x) = \cos(90^{\circ})$$
Find out what is cos(90), and f(x) is nothing by $y-value$..

anonymous · Answer

*but

anonymous · Answer

but? @eta?

anonymous · Answer

ok never mind i see it now lol thank u so very much

anonymous · Answer

but you only want answer, you do not want to learn the things.. :P

anonymous · Answer

I wrote "nothing by y-value,     there is no by, by should be but there..

anonymous · Answer

never said that wat u told me actually help me figure out my last 5 questions i have

anonymous · Answer

-.- not trying to be mean but please dont under dtimate people @eta

anonymous · Answer

Hey, do I still need to mention that I was just kidding?  I told my expression :P with that statement..

anonymous · Answer

Okay, allow me to ask for sorry, I am sorry if you felt any bad from my side.. :(