# Calculus

posted by
**Katie**
.

The function f is continuous on the closed interval [1,7] and has values in the table below

x f(x)

1 10

4 30

6 40

7 20

Usinf the subintervals [1,4] [4,6] [6,7] what is the trapezoidal apporx. of the integral from 1 to 7 of f(x)dx?

The answer: 160

I tried doing each interval as separate integrals and then using TRAP and then adding them but I got 180. How do I get the right answer?