If the operation is defined by a b = a2 + b2 for all real numbers a and b, then (2 3) 4 is equal to
120
185
175
129
If and the angle between a and b is , then the area of the triangle formed by these two vectors as two sides is
15
Let a = . If b is a vector such that a · b = and = , then is equal to
7
3
A.