INTEGRATION APPLICATIONS 1 PROGRAMME 18 INTEGRATION APPLICATIONS 1
Programme 18: Integration applications 1 Basic applications Parametric equations Mean values Root mean square (rms) values
Programme 18: Integration applications 1 Basic applications Parametric equations Mean values Root mean square (rms) values
Programme 18: Integration applications 1 Basic applications Areas under curves Definite integrals
Programme 18: Integration applications 1 Basic applications Areas under curves The area above the x-axis between the values x = a and x = b and beneath the curve in the diagram is given as the value of the integral evaluated between the limits x = a and x = b: where
Programme 18: Integration applications 1 Basic applications Areas under curves If the integral is negative then the area lies below the x-axis. For example:
Programme 18: Integration applications 1 Basic applications Definite integrals The integral with limits is called a definite integral:
Programme 18: Integration applications 1 Basic applications Definite integrals To evaluate a definite integral: Integrate the function (omitting the constant of integration) and enclose within square brackets with the limits at the right-hand end. Substitute the upper limit. Substitute the lower limit Subtract the second result from the first result.
Programme 18: Integration applications 1 Basic applications Parametric equations Mean values Root mean square (rms) values
Programme 18: Integration applications 1 Parametric equations If a curve has parametric equations then: Express x and y in terms of the parameter Change the variable Insert the limits of the parameter
Programme 18: Integration applications 1 Parametric equations For example, if x = a sin and y = b cos then the area under the curve y between = 0 and = is:
Programme 18: Integration applications 1 Basic applications Parametric equations Mean values Root mean square (rms) values
Programme 18: Integration applications 1 Mean values The mean value M of a variable y = f (x) between the values x = a and x = b is the height of the rectangle with base b – a and which has the same area as the area under the curve:
Programme 18: Integration applications 1 Basic applications Parametric equations Mean values Root mean square (rms) values
Programme 18: Integration applications 1 Root mean square (rms) values The root mean square value of y is the square root of the mean value of the squares of y between some stated limits:
Programme 18: Integration applications 1 Learning outcomes Evaluate the area beneath a curve Evaluate the area beneath a curve given in parametric form Determine the mean value of a function between two points Evaluate the root mean square (rms) value of a function