Prove that Sin^2x - cos^2x - 1 = cos x
fundamental trig identity, which provides the basis for many others:
sin^2 + cos^2 = 1
so,
sin^2 - cos^2 - 1
= 1 - cos^2 - cos^2 - 1
= -2cos^2
??
as written, not true. Is there a typo somewhere?
sin^2 + cos^2 = 1
so,
sin^2 - cos^2 - 1
= 1 - cos^2 - cos^2 - 1
= -2cos^2
??
as written, not true. Is there a typo somewhere?