#4sin(2x)=tanx#, solve for x (for #0<=x<=360#). I'm getting 7 answers, but only 4 answers are listed, and they are between #0# and #180#. Can somebody solve this?
1 Answer
Oct 13, 2015
Solve
Ans:
Explanation:
4sin 2x - tan x = 0.
4sin 2x.cos x - sin x = 0
8sinx.cos^2 x - sin x = 0
(condition
sin x(8cos^2 x - 1) = 0.
a. sin x = 0 -->
b.
a. cos x = 0.35 -->
b. cos x = - 0.35 -->
Check by calculator.
x = 69.33 --> sin 2x = 0.66 --> 4sin 2x = 2.64
tan x = tan 69.33 = 2.64. OK
x = 110.49 --> sin 2x = sin (220.98) = -0.66 --> 4sin 2x = -2.64 --> tan 110.49 = -2.67. OK