Y=2sinx-cosx on [0, 2pi]

Question

Find x- and y-intercepts

Answer 1

y=2sin(x)-cos(x)
so when x=0
y=2sin(0)-cos(0)
y=0-1
y=-1
and when y=0
0=2sin(x)-cos(x)
cos(x)=2sin(x)
cos(x)/sin(x)=2
cot(x)=2
x=cot^-1(2)
x=26.5651 which is not between 0 and 2 pi