Question

Which of the following is a trigonometric identity?

cot 0 + tan 0 = 1
sec2 0 +csc2 0 = 1
tan2 0 = sin2 0 x sec2 0
cos2 = sec2 0 x tank 0​

Answer 1

it's the first one... I think

Answer 2

third one

I'm assuming does 2's are squared symbols.

Explanation:

It's the third one because

sin^2 x sec^2 x

sin^2 x (1/cos^2 x) by reciprocal identity

sin^2 x/cos^2 x by multiplicative identity prop

tan^2 x by quotient identity

The first one wouldn't work because plugging in pi/4 gives 1+1=1 which isn't true.

The second one doesn't work because plugging in pi/4 gives 2+2=1 which isn't true.

The last equation doesn't make sense at all. There is no variable on the left and on the right there is an extra variable.