Answer:
2, 3, 4 and 7 are correc.t
Step-by-step explanation:
sec^2 x = 1 + tan^2x
so sec^2 x - 1 = tan^2 x
So the second choice is correct.
sec^2 x - cos^2x - sin^2x
= sec^2 x - (cos^2x + sin^2 x()
= sec^2 x - 1
The third is correct.
sec^2x / csc^2x = 1 / cos^2x / 1 / sin^2x
= sin^2x / cos^2x
= tan^2x
= 1 - sec^2 x
So the fourth choice is correct.
1 - cos^2x / cos^2 x
= sin^2x / soc^2x
= tan^2x
= 1 - sec^2x
The seventh choice is correct.
