Multiply both sides by sinx
3tanx*sinx = 8
tanx = sinx/cosx so the above can be written as
3*sin2x/cosx = 8
Multiply both sides by cos x
3*sin2x = 8cosx
sin2x = 1 - cos2x so the above becomes
3*(1 - cos2x) = 8cosx
3 - 3cos2x = 8cosx
Add 3cos2x to both sides of the equation
3 = 3cos2x + 8cosx
Subtract 3 from both sides of the equation
0 = 3cos2x + 8cosx - 3
.
Multiply both sides by sinx
3tanx*sinx = 8
tanx = sinx/cosx so the above can be written as
3*sin2x/cosx = 8
Multiply both sides by cos x
3*sin2x = 8cosx
sin2x = 1 - cos2x so the above becomes
3*(1 - cos2x) = 8cosx
3 - 3cos2x = 8cosx
Add 3cos2x to both sides of the equation
3 = 3cos2x + 8cosx
Subtract 3 from both sides of the equation
0 = 3cos2x + 8cosx - 3
.