exp 7-9: init

Signed-off-by: Amneesh Singh <natto@weirdnatto.in>

7.c

@@ -0,0 +1,26 @@
+#include <math.h>
+#include <stdio.h>
+
+#define f(x) ((352 * x * x * x) - (64 * x * x) + (198 * x) - 36)
+
+double simpsons_1_3(double a, double b, double n) {
+  double h = (b - a) / n;
+
+  double s = f(a) + f(b);
+
+  // Add the other heights
+
+  for (int i = 1; i < n; i += 2)
+    s += 4 * f(a + i * h);
+
+  for (int i = 2; i < n; i += 2)
+    s += 2 * f(a + i * h);
+
+  return (h / 3) * s;
+}
+
+int main() {
+  printf("The area under the curve f(x) = 352x^3 - 64x^2 + 198x - 36 from x=3 "
+         "to x=4 is %lf",
+         simpsons_1_3(3, 4, 10000));
+}