Question

i have to verify that this is an identity. secx-tanx=1-sinx/cosx........ how do i do that??

Answer 1

did you mean sinx-tanx=1-sinx/cos ?

Answer 2

Aja, if you turn everything into terms of sine and cosine it becomes a lot easier! Remember secx=1/cosx, and tanx=sinx/cosx.

Answer 3

where does secx=1?

Answer 4

Hint: At 0 + 2npi, where n is any integer.

Answer 5

Instead of thinking of when sec(x)=1 it's exactly the same to think of when cos(x)=1.