diff --git a/README.md b/README.md
index a5c0450..c997aa6 100644
--- a/README.md
+++ b/README.md
@@ -47,3 +47,23 @@ y(1)=y0;
 end
 ```
 ![](assets/README-23f54e97.png)
+
+# Problem 3
+## Part A
+The analytical solution is y = cos(3t)
+
+## Part B
+```
+dt=[.1 .001];
+figure();
+hold on
+x=[0:dt(2):3]';
+y_n=zeros(length(x),2);
+y_n(1,:)=[1,0];
+for i=2:length(x)
+        dy=prob3_ode(x,y_n(i-1,:));
+        y_n(i,:)=y_n(i-1,:)+ dt(2)*dy;
+end
+plot(x,cos(3*x),'k-',x,y_n(:,1),'o');
+```
+![](assets/README-4e4bb548.png)
diff --git a/assets/README-4e4bb548.png b/assets/README-4e4bb548.png
new file mode 100644
index 0000000..5dccf9e
Binary files /dev/null and b/assets/README-4e4bb548.png differ
diff --git a/prob3_ode.m b/prob3_ode.m
new file mode 100644
index 0000000..97cc9a1
--- /dev/null
+++ b/prob3_ode.m
@@ -0,0 +1,5 @@
+function dy=prob3_ode(t,y)
+dy=zeros(size(y));
+dy(1)=y(2);
+dy(2)=-9*y(1);
+end
\ No newline at end of file
diff --git a/prob3ptB.m b/prob3ptB.m
new file mode 100644
index 0000000..ee1e635
--- /dev/null
+++ b/prob3ptB.m
@@ -0,0 +1,11 @@
+dt=[.1 .001];
+figure();
+hold on
+x=[0:dt(2):3]';
+y_n=zeros(length(x),2);
+y_n(1,:)=[1,0];
+for i=2:length(x)
+        dy=prob3_ode(x,y_n(i-1,:));
+        y_n(i,:)=y_n(i-1,:)+ dt(2)*dy;
+end
+plot(x,cos(3*x),'k-',x,y_n(:,1),'o');
\ No newline at end of file