MATLAB: Quad error

Question

Good Afternoon All,

I am attempting to use matlab quad on a simple constant and im getting a rather large error (the calculated value is online 25% of the actual value). Say I have f(x)=10 and wish to calculate the definite integral between 0 and 5.

Then the it will be the integral of 10 dx from 0 to 5

This leads to 10x between 0 and 5 = 10(5)-10(0)=50.

When I use matlab quad I get: >> f=10;a=0;b=5; >> x=quad(inline('f'),a,b)

x =

   12.5000

Where am I going wrong with this?

Thanks,

Mel

Answer 1

out = quad(@(x)10*ones(size(x)),0,5)

OR

out = trapz([0 5],[10 10])