Question

How do I solve `4 sin x + 9 cos x = 0` for `0 < x < 360` ?

Answer 1

Refer to explanation

Explanation:

We have that
#4 sinx + 9 cosx = 0=> 4 sinx = −9 cosx => sinx/cosx = −9/4 => tanx = −9/4 #

`x = tan^(-1)(−9/4) + pi*k`, for all integers `k`

For `0° < x < 360°`
`x = tan^(-1)(−9/4) + 180 ≈ 113.96°`
`x = tan^(-1)(−9/4) + 360 ≈ 293.96°`