Find the values of (3j^)·(-4j^)

Let, A=3j^ and B=(-4j^)A=0i^+3j^+0k^ and B=0i^-4j^+0k^Also, A·B=ABcos θSince both A and B are on the same axis, the value of θ is 0Therefore, A·B=ABcos⇒A·B=(3)(-4)cos0°=-12