Question

Use factoring, the quadratic formula, or identities to solve the equation. Find the solution in the interval [0, 2π).
4 sin^2(x) + 5 sin (x) = 9

Answer 1

\[
4 u^2 - 5 u - 9=(1+u)(-9+4u)\\
4 \sin^2(x) - 5 \sin(x) -9=( 1+ \sin(x))(-9 + 4 \sin(x))\\
( 1+ \sin(x))(-9 + 4 \sin(x))=0\\
\]
You can finish it now.

Answer 2

thank you