Required to Prove the following trig identity:
(cos2x)^2 + (sin2x)^2 = 1
Can you use the Pythagorean theorem?
If so, draw a right trangle, label the sides, and angles.
change cosine x to adjacent/hyp
change sin x to opposite/hyp
substitute in the hypothesis:
(adj/hyp)^2 + (Opp/hyp)^2=1
(adj^2 + opp^2)/Hyp^2=1
hyp^2/hyp^2=1
1=1