Question

Which of the following is an identity. (All that apply)

Answer 1

Will Give medal!!!

Answer 2

to show if something is an identity you need to transform one side of the = sign to gget the other

Answer 3

Thnxs. I had a brain fart!!!

Answer 4

for example, the last relation
we know that
sin2x = 2sinxcosx
- so if you replace the x by 4x you can see that this is an identity

Answer 5

sin 2(4x) = 2 sin 4x cos 4x
sin 8x = 2 sin4x cos4x

Answer 6

you need to use known trig identities

Answer 7

C:

we know that tan2x = tan^2 x
--------
1 - tan^2x

Answer 8

so 1 / tan2x = ?