Use a suitable change of variables to determine the indefinite integral. (Use C for the constant of integration.)∫(sin2(θ)−2sin(θ))(sin3(θ)−3sin2(θ))3cos(θ)dθ
Q. Use a suitable change of variables to determine the indefinite integral. (Use C for the constant of integration.)∫(sin2(θ)−2sin(θ))(sin3(θ)−3sin2(θ))3cos(θ)dθ
Define u and du: Let u=sin3(θ)−3sin2(θ), then du=(3sin2(θ)cos(θ)−6sin(θ)cos(θ))dθ.
Rewrite in terms of u: Rewrite the integral in terms of u: ∫((sin2(θ)−2sin(θ))⋅u3⋅cos(θ))dθ=∫((sin2(θ)−2sin(θ))⋅(sin3(θ)−3sin2(θ))3⋅cos(θ))dθ.
Substitute du and u: Substitute du and u into the integral: ∫((sin2(θ)−2sin(θ))⋅u3⋅cos(θ))dθ=∫(u3⋅(3sin2(θ)−6sin(θ)))dθ.
Factor out constants: Factor out constants from du: du=3(sin2(θ)−2sin(θ))cos(θ)dθ.
Integrate u3: Now the integral becomes ∫(u3⋅(31)du)=(31)∫(u3du).
Substitute back for u: Integrate u3 with respect to u: (1/3)∫(u3du)=(1/3)(u4/4)+C.
Simplify the expression: Substitute back for u: 31(4u4)+C=31(4(sin3(θ)−3sin2(θ))4)+C.
Simplify the expression: Substitute back for u: (31)(4u4)+C=(31)((sin3(θ)−3sin2(θ))4/4)+C. Simplify the expression: (31)((sin3(θ)−3sin2(θ))4/4)+C=(121)(sin3(θ)−3sin2(θ))4+C.
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