I'm working through a problem set for a class unlrelated to trigonometry, but reached a dead end when I failed to recognize that
\(\displaystyle 2cos^2(x)- sin^2(x) = 3cos^2(x)-1\)
Could somebody kindly show me why this is the case? (I've never actually taken a formal trigonometry class, so my background is fairly weak).
Thanks.
\(\displaystyle 2cos^2(x)- sin^2(x) = 3cos^2(x)-1\)
Could somebody kindly show me why this is the case? (I've never actually taken a formal trigonometry class, so my background is fairly weak).
Thanks.