Rm the addition or subtraction and use the fundamental ident

Rm the addition or subtraction and use the fundamental identities to simplify. There is more than one correct form of the answer. Factor the expression and use the fundamental identities to simplify. There is more than one correct form of the answer. 8 tan^2 x - 8 tan^2 x sin^2 x

Solution

9.

{9/(1+cosx)} + {9/(1-cosx)} = 9*2/(1-cos²x) = 18/sin²x = 18 cosec²x

10.

8 tan²x - 8 tan²x sin²x = 8 tan²x(1-sin²x) = 8 tan²x (cos²x) = 8 (sin²x/cos²x) * cos²x = 8sin²x.