divide both sides by cosx
4 sinx/cosx = 1
4 tanx = 1
tanx = 1/4
x = arctan(1/4) = 14.04°
but the tangent is also positive in quad III
so x = 180+14.04 = 194.04°
x = 14.04° or 194.04°
solve
4 sin x = cos x for 0<X<360
2 answers
how do i know if the tangent is positive in the third quadrant?