Ok this may be more of an algebra question than a trig one but it originated from a trig one. Any help would be much appreciated...

Solve the following equation for theta giving your answers in the interval from -180 to 180:

4sin'theta'cos'theta' + 1 = 2(sin'theta' + cos'theta')

After multiplying out the brackets, squaring the expression and substituting cos^2'theta' for 1-sin^'theta' I get the following:

16sin^2'theta' - 16sin^4'theta' = 3

However I can't seem to simplify this further to enable me to find 'theta'. Can someone show me how to do this...and say if the approach I have used is the quickest way of solving this equation?

Thanks