Solve ∫ (from 1 to 2) of (x-y) wrt x

$$\int _ { 1 } ^ { 2 } ( x - y ) d x$$

Evaluate

$$\frac{3}{2}-y$$

Solution Steps

Evaluate the indefinite integral first.

$$\int x-y\mathrm{d}x$$

Integrate the sum term by term.

$$\int x\mathrm{d}x+\int -y\mathrm{d}x$$

Factor out the constant in each of the terms.

$$\int x\mathrm{d}x-\int y\mathrm{d}x$$

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

$$\frac{x^{2}}{2}-\int y\mathrm{d}x$$

Find the integral of y using the table of common integrals rule \int a\mathrm{d}x=ax.

$$\frac{x^{2}}{2}-yx$$

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.

$$\frac{2^{2}}{2}-y\times 2-\left(\frac{1^{2}}{2}-y\right)$$

Simplify.

$$\frac{3}{2}-y$$

Differentiate w.r.t. y

$$-1$$