Question

sin theta=-8/17
Find cos2theta

Answer 1

Do you mean \(\cos^2\theta\)?

Answer 2

Double angle formulae..

Answer 3

\( \color{Black}{\Rightarrow \sin^2\theta + \cos^2\theta = 1 }\)

Answer 4

If it is supposed to be \(\sin^2\theta\) ^

Answer 5

when pi is less than theta which is less than three pi divided by two

Answer 6

\(cos2x=cos^{2}x-sin^{2}x => 2cos^{2}x-1 => 1-sin^{2}x\)

Answer 7

No, ParthKohli, its just multiplied by two. I dont understand :(

Answer 8

\[sin\theta = -\frac{8}{17}\] Then sub it in the formula. Since \(cos2x\) is a double angle formulae

Answer 9

Find \(cos2\theta\) right?