Use the double angle formula to rewrite the equation y = 4sin^2 (slashed zero) - 2.

Question

anonymous · Answer

is the slashed zero theta?

anonymous · Answer

Yes.

anonymous · Answer

it reduces to $$y = -2 \cos(2\theta)$$

anonymous · Answer

Can you show me how it works?

anonymous · Answer

You need to simply use that cos(2A) = 1- 2 sin^2(A)

anonymous · Answer

so from this we take theta to be A

anonymous · Answer

if you rewrite the equation you gave in that form it becomes..

-2 + 4sin^2(A)

anonymous · Answer

from here we can factor out a -2 which leaves us with -2(1-2sin^2(A))


and you can see that the values under the parenthesis is just cos(2A) from the identity. 

So the answer you end up with after plugging in theta for A, is just -2cos(2Theta)

anonymous · Answer

do you understand?

anonymous · Answer

Yes. Thank you for giving a detailed explanation.

anonymous · Answer

yeah no problem, glad i could help