Substitution and Simplification: Substitute x=2sec(θ) into the integral and simplify.∫xx2−42dx=∫2sec(θ)4sec2(θ)−42⋅2sec(θ)tan(θ)dθ=∫2sec(θ)4(tan2(θ)+1)−42⋅2sec(θ)tan(θ)dθ=∫2sec(θ)4tan2(θ)2⋅2sec(θ)tan(θ)dθ=∫2sec(θ)⋅2tan(θ)2⋅2sec(θ)tan(θ)dθ=∫4tan(θ)2⋅2sec(θ)tan(θ)dθ=∫(21)dθ
Integration and Simplification: Integrate (21)dθ from 0 to 3π. ∫(21)dθ=(21)θ Evaluating from 0 to 3π gives us: (21)θ∣ from 0 to 3π = (21)(3π)−(21)(0)=6π
Evaluation and Conversion: Convert the result back to x. Since we made the substitution x=2sec(θ), we need to find the corresponding θ values for x=2 and x=4. However, we already have these values from the substitution step: θ=0 when x=2 and θ=3π when x=4. Therefore, the definite integral from 2 to x=2sec(θ)0 of the function x=2sec(θ)1 with respect to x is x=2sec(θ)3.
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