Bytelearn - cat image with glassesAI tutor

Welcome to Bytelearn!

Let’s check out your problem:

1616. If sin2θ+sinθ=1\sin ^2 \theta+\sin \theta=1, then show that cos2θ+cos4θ=1\cos ^2 \theta+\cos ^4 \theta=1

Full solution

Q. 1616. If sin2θ+sinθ=1\sin ^2 \theta+\sin \theta=1, then show that cos2θ+cos4θ=1\cos ^2 \theta+\cos ^4 \theta=1
  1. Rewrite Equation: Rewrite the given equation using the Pythagorean identity sin2θ+cos2θ=1\sin^2 \theta + \cos^2 \theta = 1.sin2θ+sinθ=1\sin^2 \theta + \sin \theta = 1sin2θ+sinθ+cos2θ=1+cos2θ\sin^2 \theta + \sin \theta + \cos^2 \theta = 1 + \cos^2 \theta
  2. Subtract to Isolate: Subtract sinθ\sin \theta from both sides to isolate cos2θ\cos^2 \theta.sin2θ+cos2θ=1sinθ\sin^2 \theta + \cos^2 \theta = 1 - \sin \theta
  3. Replace with Identity: Use the Pythagorean identity again to replace sin2θ+cos2θ\sin^2 \theta + \cos^2 \theta with 11.1=1sinθ1 = 1 - \sin \theta
  4. Add to Find Value: Add sinθ\sin \theta to both sides to find the value of sinθ\sin \theta.sinθ=0\sin \theta = 0

More problems from Solve exponential equations by rewriting the base