How do you prove the identities?

1) 1- cos²θ ≡ sin²θ
2) (1-sin²θ) tanθ≡ cosθ sinθ

im not quite sure if this is right but i got 5.6 oisutuve

step-by-step explanation:

for this case we have by definition, if two lines are perpendicular, then the product of their slopes is -1.

then, given the following line:

so,

we are looking for m_ {2}:

then, the line is given by:

we find "b" replacing the given point:

finally, the equation is:

option c