Identify Integral: Let's start by identifying the integral we need to evaluate:I=∫2x2e4xdxThis integral suggests the use of integration by parts, where we let one part be differentiated and the other be integrated. We can choose u=x2 and dv=2e4xdx.
Choose u and dv: Now we need to find du and v. Differentiating u gives us du=2xdx, and integrating dv gives us v=(21)e4x (since the integral of eax is (a1)eax).
Find du and v: Applying the integration by parts formula, ∫udv=uv−∫vdu, we get:I=uv−∫vduI=x2⋅(21)e4x−∫(21)e4x⋅2xdx
Apply Integration by Parts: Simplify the integral:I=21x2e4x−∫xe4xdxNow we need to apply integration by parts again to the remaining integral, ∫xe4xdx. This time, let's choose u=x and dv=e4xdx.
Simplify Integral: Differentiating u gives us du=dx, and integrating dv gives us v=41e4x.
Apply Integration by Parts Again: Applying the integration by parts formula again, we get:I=21x2e4x−(x⋅41e4x−∫41e4xdx)
Simplify Integral: Simplify the integral and calculate the last integral:I=21x2e4x−41xe4x+41×41e4xI=21x2e4x−41xe4x+161e4x
Calculate Last Integral: Finally, we add the constant of integration C to our result:I=(21)x2e(4x)−(41)xe(4x)+(161)e(4x)+C
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