Question

Express sin(pi/2 - x) in terms of cosx

Answer 1

\[\sin ^{2}\theta + \cos ^{2}\theta = 1\]

Answer 2

\[\sin \theta = \sqrt{1-\cos ^{2}x} \]

Answer 3

There should be a theta beside cos^2 instead of an x.

What should I do from here?

Answer 4

so you know the "cofunction" identities?

Answer 5

i don't think this is the right track for this one
it is true that \(\sin(\frac{\pi}{2}-\theta)=\cos(\theta)\)

Answer 6

you can use the addition angle formula
or you can keep track of the translations of the graph from \(y=\sin(\theta)\) to \(y=\sin(\frac{\pi}{2}-\theta)\)

Answer 7

easiest to use
\[\sin(\alpha -\beta)=\sin(\alpha)\cos(\beta)-\sin(\beta)\cos(\alpha)\] with \[\alpha =\frac{\pi}{2},\beta=x\]

Answer 8

you will get it right away

Answer 9

Thats alot of trig id's, thanks! I think I can do it from here.