Identify integral: Identify the integral to be solved.We need to evaluate the integral of the function 6x2⋅23x with respect to x.I=∫6x2⋅23xdx
Recognize integral type: Recognize that the integral involves a product of a polynomial and an exponential function.This integral does not have a straightforward antiderivative, so we will need to use integration by parts.Integration by parts formula: ∫udv=uv−∫vdu
Choose u and dv: Choose u and dv. Let u=6x2 (which will become simpler when differentiated) and dv=23xdx (which will remain the same when integrated).
Differentiate and integrate: Differentiate u and integrate dv. du=d(6x2)=12xdx v=∫2(3x)dx To integrate v, we need to use the fact that ∫a(f(x))f′(x)dx=ln(a)a(f(x))+C, where a is a constant and f(x) is a function of x.
Integrate dv to find v: Integrate dv to find v.v=∫2(3x)dx=3ln(2)2(3x)+C
Apply integration by parts: Apply the integration by parts formula.I=uv−∫vduI=(6x2)⋅(3ln(2)23x)−∫(3ln(2)23x)⋅(12x)dx
Simplify the expression: Simplify the expression.I=ln(2)2x2⋅23x−ln(2)4⋅∫x⋅23xdxNow we have a new integral to solve, which is again a product of a polynomial and an exponential function.
Apply integration by parts again: Apply integration by parts to the new integral.Let u=x and dv=23xdx for the new integral.du=dxv=∫23xdx=3ln(2)23x+C (as calculated before)
Integrate new integral: Apply the integration by parts formula to the new integral.Inew=uv−∫vduInew=x⋅(3ln(2)23x)−∫(3ln(2)23x)dx
Apply integration by parts to new integral: Integrate the remaining integral.∫3ln(2)23xdx=9ln(2)223x+C
Integrate remaining integral: Substitute Inew back into the original integral.I=(ln(2)2x2⋅23x)−(ln(2)4)⋅(x⋅(3ln(2)23x)−(9ln(2)223x))
Substitute Inew: Simplify the expression.I=ln(2)2x2⋅23x−3ln(2)24x⋅23x+9ln(2)34⋅23x+C
Simplify the expression: Combine the terms and write the final answer.I=ln(2)2x2⋅23x−3ln(2)24x⋅23x+9ln(2)34⋅23x+C
More problems from Find indefinite integrals using the substitution and by parts