diff --git a/pset6/5-exp.c b/pset6/5-exp.c
new file mode 100644
index 0000000..4342b9c
--- /dev/null
+++ b/pset6/5-exp.c
@@ -0,0 +1,49 @@
+#include <math.h>
+#include <stdio.h>
+
+// Function prototypes
+double expe(double x);
+double my_pow(double x, double l);
+double get_sing(double x, int l);
+
+int main(void) {
+  // Initial variables
+  double x;
+  scanf("%lf", &x);
+
+  printf("%.4lf\n", expe(x));
+  return 0;
+}
+
+double expe(double x) {
+  double ans = 0;
+  double addup;
+  for (int i = 0;; i++) {
+    addup = (get_sing(x, i));
+    if (fabs(addup) < 1e-8) {
+      break;
+    }
+    ans += addup;
+  }
+  return ans;
+}
+
+double my_pow(double x, double l) {
+  double ans = 1;
+  for (long long i = 0; i < l; i++) {
+    ans *= x;
+  }
+  return ans;
+}
+
+double get_sing(double x, int l) {
+  if (l <= 0) {
+    return 1;
+  } else {
+    double ans = my_pow(x, l);
+    for (int i = l; i > 1; i--) {
+      ans /= i;
+    }
+    return ans;
+  }
+}