# Trigonometric functions

For zero degrees < x < ninety degrees, how many solutions are there for the equation

2sin x = cos x

https://brainmass.com/math/trigonometry/working-trigonometric-functions-4216

#### Solution Preview

2sinx=cosx

sinx/cosx=1/2

tanx=1/2

x=arctan(1/2)

tanx is a strictly increasing function on the interval 0<x<90

so there is only ...

#### Solution Summary

This determines the number of solutions of a trigonometric equation.

$2.19