What's the difference between the sum of squares of a and B and the sum of squares of a and B? The sum of the squares of a and B The sum of squares of a and B

What's the difference between the sum of squares of a and B and the sum of squares of a and B? The sum of the squares of a and B The sum of squares of a and B

The sum of the squares of a and B denotes a + B & sup2;
The sum of squares of a and B denotes a & sup2; + B & sup2;
The square of the sum of a and B denotes (a + b) & sup2;