Exercise is mixed —some require integration by parts, while others can be integrated by using techniques discussed in the chapter on Integration.
∫(8x+10) ln (5x) dx.

Respuesta :

Answer:

[tex]\text{ln}(5x)(4x^2+10x)-2x^{2}-10x+C[/tex]

Step-by-step explanation:

We have been given an definite integral [tex]\int \left(8x+10\right)\:\text{ln}\:\left(5x\right)\:dx[/tex]. We are asked to find the integral using integration by parts.

We will use Integration by parts formula to solve our given problem.

[tex]\int\ vdv=uv-\int\ vdu[/tex]

Let [tex]u=\text{ln}(5x)[/tex] and [tex]v'=8x+10[/tex].

Now, we need to find du and v using these values as shown below:

[tex]\frac{du}{dx}=\frac{du}{dx}(\text{ln}(5x))[/tex]

Using chain rule, we will get:

[tex]\frac{du}{dx}=\frac{1}{5x}*5[/tex]

[tex]\frac{du}{dx}=\frac{1}{x}[/tex]

[tex]du=\frac{1}{x}dx[/tex]

[tex]v'=8x+10[/tex]

[tex]v=\frac{8x^{1+1}}{2}+10x[/tex]

[tex]v=\frac{8x^{2}}{2}+10x[/tex]

[tex]v=4x^{2}+10x[/tex]

Upon substituting these values in integration by parts formula, we will get:

[tex]\int\left(8x+10\right)\:\text{ln}\:\left(5x\right)\:dx=\text{ln}(5x)(4x^2+10x)-\int\ (4x^2+10x)\frac{1}{x}dx[/tex]

[tex]\int\left(8x+10\right)\:\text{ln}\:\left(5x\right)\:dx=\text{ln}(5x)(4x^2+10x)-\int\ \frac{4x^2}{x}+\frac{10x}{x}dx[/tex]

[tex]\int\left(8x+10\right)\:\text{ln}\:\left(5x\right)\:dx=\text{ln}(5x)(4x^2+10x)-\int 4x+10dx[/tex]

[tex]\int\left(8x+10\right)\:\text{ln}\:\left(5x\right)\:dx=\text{ln}(5x)(4x^2+10x)-(\frac{4x^{2}}{2}+10x)+C[/tex]

[tex]\int\left(8x+10\right)\:\text{ln}\:\left(5x\right)\:dx=\text{ln}(5x)(4x^2+10x)-2x^{2}-10x+C[/tex]

Therefore, our required integral would be [tex]\text{ln}(5x)(4x^2+10x)-2x^{2}-10x+C[/tex].