Problem 5

Question

Find the integral. $$ \int \frac{x^{3}}{x^{2}+1} d x $$

Step-by-Step Solution

Verified
Answer
The solution to the integral is \(0.5(x^{2}+1) + C\).
1Step 1: Express the denominator function in terms of its derivative
Firstly, observe that the derivative of \(x^{2} + 1\) is \(2x\), which can be found in the numerator. So, if we let \(u = x^{2}+1\), then du = \(2x dx\). However, we need \(x dx\), not \(2x dx\). To adjust for this, we can write \(x dx = 0.5 * du\). The integral now becomes \(\int \frac{0.5*u*du}{u}\).
2Step 2: Simplify the Integral and Evaluate
The integral simplifies to \(\int 0.5 du\) to which the answer is \(0.5u + C\).
3Step 3: Substitute Back
Change \(u\) back to the original variable. The final result is \(0.5(x^{2}+1) + C\).