Corrected derivatives.

modsim/ass2/q4.c

@@ -14,7 +14,7 @@ double f1(double x) {
 }
 
 double df1(double x) {
-    return x / 2 - 1;
+    return 2 * x - 1;
 }
 
 double f2(double x) {
@@ -22,7 +22,7 @@ double f2(double x) {
 }
 
 double df2(double x) {
-    return (x * x) / 3 - 3;
+    return 3 * x * x - 3;
 }
 
 double f3(double x) {
@@ -30,11 +30,9 @@ double f3(double x) {
 }
 
 double df3(double x) {
-    return (x * x + 1) + (x / 2) * (x - 4);
+    return (x * x + 1) + 2 * x  * (x - 4);
 }
 
-#define TEST(i) (printf("f1: %.11f\n", &f(i), &df(i), 1))
-
 int main(void) {
     printf("f1: %.11f\n", newton(&f1, &df1, 1));