Solve ∫ (from - 2 to 2) of (4x^2-x^4) wrt x

$$\int _ { - 2 } ^ { 2 } ( 4 x ^ { 2 } - x ^ { 4 } ) d x$$

Evaluate

$$\frac{128}{15}\approx 8.533333333$$

Solution Steps

Evaluate the indefinite integral first.

$$\int 4x^{2}-x^{4}\mathrm{d}x$$

Integrate the sum term by term.

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

Factor out the constant in each of the terms.

$$4\int x^{2}\mathrm{d}x-\int x^{4}\mathrm{d}x$$

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 4 times \frac{x^{3}}{3}.

$$\frac{4x^{3}}{3}-\int x^{4}\mathrm{d}x$$

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}. Multiply -1 times \frac{x^{5}}{5}.

$$\frac{4x^{3}}{3}-\frac{x^{5}}{5}$$

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.

$$\frac{4}{3}\times 2^{3}-\frac{2^{5}}{5}-\left(\frac{4}{3}\left(-2\right)^{3}-\frac{\left(-2\right)^{5}}{5}\right)$$

Simplify.

$$\frac{128}{15}$$