Given Integral: We are given the integral: ∫36−16x2−9dxTo solve this, we can recognize that this integral is in the form of an integral that results from a trigonometric substitution. Specifically, we can use the substitution x=43sin(θ) to simplify the square root term.
Trigonometric Substitution: First, let's make the substitution x=43sin(θ). Then, dx=43cos(θ)d(θ). We also need to express the square root in terms of θ. Substituting x into the square root gives us 36−16x2=36−16(43)2sin2(θ)=36−9sin2(θ).
Simplify Square Root: Now, we simplify the square root: 36−9sin2(θ)=36(1−sin2(θ))=36cos2(θ)=6cos(θ). We can now substitute x and dx into the integral and replace the square root with 6cos(θ).
Substitute x and dx: The integral becomes: ∫6cos(θ)−9⋅(43)cos(θ)d(θ)=∫(−9⋅43)d(θ)=∫(−427)d(θ)
Integrate: Integrating −427 with respect to θ gives us:−427⋅θ+C
Back-Substitute for x: Now we need to back-substitute to get the answer in terms of x. From our substitution x=43sin(θ), we can solve for θ: θ=arcsin(34x).
Final Answer: Substituting θ back into our integral result gives us:−427⋅arcsin(34x)+CThis is our final answer in terms of x.
More problems from Find indefinite integrals using the substitution