Question

Find cos2 theta given the cos is 4/5

Answer 1

I have no idea how to do this question. Would you just multiply it That would give you 16/ 25

Answer 2

@diamolnd2 do you mean \[\cos^{2} \theta?\]
\[\cos^{2} \theta = (\cos \theta)^{2}\]

Answer 3

no its not squared

Answer 4

sin2\[\theta \] + cos\[\theta \] = 0

Answer 5

sorry thats a different problem, im confused on that one two though

Answer 6

if it's not squared, do you mean
\[\cos 2\theta?\]
you can use this formula:
\[\cos 2\theta=2\cos^{2} \theta-1\]

Answer 7

yes that was what i ment

Answer 8

2(16/25)-1
=7/25