Question

How do you simplify `(cos^2alpha-1)/(cosalpha+1)`?

Answer 1

`=> cosalpha - 1, alpha !=pi`

Explanation:

Factor the expression in the numerator as a difference of squares.

`=>((cosalpha + 1)(cosalpha - 1))/(cosalpha + 1)`

`=> (cancel(cosalpha + 1)(cosalpha - 1))/(cancel(cosalpha + 1))`

`=> cosalpha - 1, alpha !=pi`

Hopefully this helps!