Solve ∫ (from 1 to 2) of x^4+3x^2

$$\int _ { 1 } ^ { 2 } x ^ { 4 } + 3 x ^ { 2 }$$

Evaluate

$$\frac{66}{5}=13.2$$

Solution Steps

Evaluate the indefinite integral first.

$$\int x^{4}+3x^{2}\mathrm{d}x$$

Integrate the sum term by term.

$$\int x^{4}\mathrm{d}x+\int 3x^{2}\mathrm{d}x$$

Factor out the constant in each of the terms.

$$\int x^{4}\mathrm{d}x+3\int x^{2}\mathrm{d}x$$

Since \int x^{k}\mathrm{d}x=\frac{x^{k+1}}{k+1} for k\neq -1, replace \int x^{4}\mathrm{d}x with \frac{x^{5}}{5}.

$$\frac{x^{5}}{5}+3\int x^{2}\mathrm{d}x$$

Since \int x^{k}\mathrm{d}x=\frac{x^{k+1}}{k+1} for k\neq -1, replace \int x^{2}\mathrm{d}x with \frac{x^{3}}{3}. Multiply 3 times \frac{x^{3}}{3}.

$$\frac{x^{5}}{5}+x^{3}$$

The definite integral is the antiderivative of the expression evaluated at the upper limit of integration minus the antiderivative evaluated at the lower limit of integration.

$$\frac{2^{5}}{5}+2^{3}-\left(\frac{1^{5}}{5}+1^{3}\right)$$

Simplify.

$$\frac{66}{5}$$