The number of values in the interval –π ≤ x ≤ π that satisfy the equation sin x = 2 cos x is

1
2
3
4
0

1 answer

sinx = 2cosx
tanx = 2

tanx > 0 in QI or QIII, so there are two values for x.

Verify this at

http://www.wolframalpha.com/input/?i=solve+sinx+%3D+2cosx