ModSim ass2: Implemented Simpson's Rule as calculation instead of weighted average.

modsim/ass2/integral.c

@@ -9,7 +9,8 @@ double trapezoidal(func_ptr f, double a, double b) {
 }
 
 double simpson(func_ptr f, double a, double b) {
-    return (2 * rectangle(f, a, b) + trapezoidal(f, a, b)) / 3;
+    //return (2 * rectangle(f, a, b) + trapezoidal(f, a, b)) / 3;
+    return (b - a) / 6 * (f(a) + 4 * f((a + b) / 2) + f(b));
 }
 
 double gauss(func_ptr f, double a, double b) {