How do you solve Sin2x cosx - cos2x sinx = 1/2sin2xcosxcos2xsinx=12?

1 Answer

x=pi/6, (5pi)/6x=π6,5π6 or

x=30^@, 150^@x=30,150

Explanation:

From sum and difference formulas

We have

sin (x+y)=sin x cos y + cos x sin ysin(x+y)=sinxcosy+cosxsiny
sin (x-y)=sin x cos y - cos x sin ysin(xy)=sinxcosycosxsiny

sin (2x-x)=sin 2x cos x - cos 2x sin xsin(2xx)=sin2xcosxcos2xsinx

sin x=sin 2x cos x - cos 2x sin xsinx=sin2xcosxcos2xsinx

So

sin x=1/2sinx=12

x=sin^-1 (1/2)=pi/6, (5pi)/6x=sin1(12)=π6,5π6

have a nice day !