Ron G. answered • 06/22/19
Multiple levels Math, Science, Writing
The trapezoidal rule is a commonly-used approximation for an exact integral. I put together a quick spreadsheet to do this calculation, and I made the assumption that I took a step of dx = 1 for each calculation. I am not sure what the 88 in your question represents, which means I may not hit the answer you want on the nose.
current value of integral = last value of integral + (1/2) (current value of f(x) + last value of f(x)) dx
With the trapezoidal rule formula above and the dx = 1 assumption, I basically went through nine steps, and at the end of the ninth step the current value of the integral was 67.24. If you follow the same steps I did, you will get the same answer. If you use a smaller value of dx you will get closer to the exact answer.
And if you have advanced far enough in the class to be able to find the exact solution, I recommend you do so to have something to compare to.
