SOLUTION: 7sin(2x)+7sin(x)=0

Algebra ->  Trigonometry-basics -> SOLUTION: 7sin(2x)+7sin(x)=0      Log On


   

Question 958632: 7sin(2x)+7sin(x)=0
Answer by Edwin McCravy(20060) About Me  (Show Source):
You can put this solution on YOUR website!
7sin(2x)+7sin(x)=0

Divide every term by 7

7sin%282x%29%2F7%2B7sin%28x%29%2F7=0%2F7

sin%282x%29%2Bsin%28x%29=0

2sin%28x%29cos%28x%29%2Bsin%28x%29=0

sin%28x%29%282cos%28x%29%2B1%5E%22%22%29=0

sin(x) = 0;   2cos(x)+1 = 0
                 cos(x) = -1%2F2
                   

If your problem states in the interval from 0° to 360°,
the answer is  0°,180°, 120°,240°

If your problem states in the interval from 0 to 2π,
the answer is  0,π,2π/3,4π/3 

If your problem states for all x in degrees, 
the answer is  180n°, 120°+360n°, 240180°+360n180°

If your problem states for all x (in radians), 
the answer is  n*π, 2π/3+2n*π, 4π/3+2n*π

Edwin