Solve ∫ (from 1 to 100) of (3/x^2)

$$\int _ { 1 } ^ { 100 } ( 3 / x ^ { 2 } )$$

Evaluate

$$\frac{297}{100}=2.97$$

Solution Steps

Evaluate the indefinite integral first.

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

Factor out the constant using \int af\left(x\right)\mathrm{d}x=a\int f\left(x\right)\mathrm{d}x.

$$3\int \frac{1}{x^{2}}\mathrm{d}x$$

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

$$-\frac{3}{x}$$

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.

$$-3\times 100^{-1}+3\times 1^{-1}$$

Simplify.

$$\frac{297}{100}$$