## anonymous 5 years ago Use the double angle formula to rewrite the equation y = 4sin^2 (slashed zero) - 2.

1. anonymous

is the slashed zero theta?

2. anonymous

Yes.

3. anonymous

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

4. anonymous

Can you show me how it works?

5. anonymous

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

6. anonymous

so from this we take theta to be A

7. anonymous

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

8. anonymous

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)

9. anonymous

do you understand?

10. anonymous

Yes. Thank you for giving a detailed explanation.

11. anonymous

yeah no problem, glad i could help