Identify Integral: Identify the integral to solve: ∫−6π3πcos2x−sinxdx. Recognize this as a standard integral involving trigonometric identities.
Use Substitution: Use substitution:Let u=cos(x), then du=−sin(x)dx.Rewrite the integral in terms of u:∫cos2(x)−sinxdx=∫u2du.
Rewrite Integral: Calculate the new limits of integration:When x=−6π, cos(−6π)=cos(6π)=3/2.When x=3π, cos(3π)=1/2.So, the limits change from u=3/2 to u=1/2.
Calculate New Limits: Evaluate the integral: ∫u2du from 3/2 to 1/2 = [−1/u] from 3/2 to 1/2. Calculate: [−1/(1/2)]−[−1/(3/2)] = −2+2/3. Simplify: −2+2/3 = (−6+23)/3.
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