How do you find the error that occurs when the area between the curve y=x^3+1y=x3+1 and the x-axis over the interval [0,1] is approximated by the trapezoid rule with n = 4?

1 Answer
Mar 6, 2015

Assuming that you want the actual error, use the fundamental theorem of calculus to get the exact value of int_0^1(x^3+1)dx10(x3+1)dx Then find the difference (subtract) from the trapezoid approximation.

I guess it's easy to see that
int_0^1(x^3+1)dx=(x^4/4+x)]_0^1=(1/4+1)-(0)=4/5=1.2510(x3+1)dx=(x44+x)]10=(14+1)(0)=45=1.25.
The trapezoid rule with n=4n=4 gives 1.2656251.265625

The error, then is 0.0156250.015625.