Question #9b19b

1 Answer
Jan 7, 2018

x=sin^-1(sqrt5 /5 )x=sin1(55)

Explanation:

Assuming your problem is: 4cos^2x=sin^2x+34cos2x=sin2x+3

Using sin^2x+cos^2x=1sin2x+cos2x=1, we get

4(1-sin^2x)=sin^2x+34(1sin2x)=sin2x+3

4-4sin^2x=sin^2x+344sin2x=sin2x+3

5sin^2x=15sin2x=1

sin^2x=0.2sin2x=0.2

=> sinx = sqrt0.2 = sqrt5 / 5 sinx=0.2=55

x=color(red)(sin^-1(sqrt5 / 5 )~~0.4647x=sin1(55)0.4647 color(red)(radrad