# A-level Mathematics/Edexcel/Core 1/Integration

## Basics of integration

editIntegration is the opposite of differentiation. For a power of x, you add 1 to the power, divide by the new power and add c, the constant of integration. Note that this rule will not work when the power of x is -1, this requires more advanced methods. The constant of integration is required because if a constant (i.e. a number without x in it) is differentiated it will become zero, and from just integration there is no way to determine the value of this constant.

For example:

becomes:

## Integrating fractions

editFractions with an x term in the denominator cannot be integrated as they are; the x term must be brought up to the working line. This can be done easily with the laws of indices.

For example:

## Determining the value of c

editYou may be given a point on a curve and asked to determine the value of the constant of integration, c. This is quite simple, as the point is given as ; the values of x and y can be plugged in and the equation solved for c.

Worked example:

- The gradient of the curve c is given by .

- The point lies on c. Hence, find the equation for c.

- Plug in values x = 3, y = 12.