Question #ca9fe
2 Answers
Use trigonometric identities as done below
Explanation:
We will make use of the identities below, found here and here . As for why we choose these identities, I can only refer to practice and intuition.
1.
2.
3.
4.
5.
Rewrite
use identity 3.
Put on common denominator by multiplying the first term by
Substitute the
Simplify (and mind the sign when removing the parenthesis)
Use identity 4 and write the denominator as a factor, for clarity
Use identity 2.
and we have arrived at what we wanted to show.