Q:

I really need help with these questions:Use basic identities to find the simplified expression-1. (cos^2 x + sin^2 x) / (cot^2 x - csc^2 x)2. cosine θ^2 / sine θ^2 + csc θ sin θExplanations would be greatly appreciated

Accepted Solution

A:
If we take the Pythagorean identity identity sin^2 x + cos^2 x = 1 then
                          (cos^2 x + sin^2 x) / (cot^2 x - csc^2 x)
The numerator becomes 1 since addition order matters not.
                                                 1 / (cot^2 x - csc^2 x)
If we factor the denominator out a negative
                                                1 / -(csc^2 x - cot^2 x)
Consider sin^2 x + cos^2 x = 1. Divide both sides by sin^2 x to get
                                         1 + cot^2 x = csc^2 x
Subtract both sides by cot^2 x to get 1 = csc^2 x - cot^2 x.
Replace the denominator
                                                 1 / -(1) = -1
For cos^2 θ / sin^2 θ + csc θ sin θ, we use cscθ = 1/sinθ and cosθ/sinθ = cotθ so
                                = cos^2 θ / sin^2 θ + 1
                                = cot^2 θ + 1
We use 1 + cot^2 θ = csc^2 θ to simplify this to
                              = csc^2 θ

Answers:         -1
                          csc^2 θ