will someone just check my answers? I am having trouble getting the hang of big oh notation, so my teacher gave me some extra practice to turn in. I just wanted to see if I was on the correct track. Code: void Ex2(int n){ int a; for (int i=0; i<n; i+=2)a=i; } f(n)=n+2 O(n) void Ex3(int n){ int a; for(int i=0; i<n*n;i++) a=i; } f(n)=n^2-1 O(n^2) void Ex4(int n){ int a; for(int i=0; i<n; i++) for(int j=0; j<=i;j++) a=i; } f(n)=??? O(n^2) void Ex5(int n){ int a; for(int i=0; i<n*n;i++) for( int j=0; i<=i; j++) a=i: } f(n)=n^2(n(n+1)/2) O(n^4)