Question

Find a.b if a=(2,-8) and b=(-1,4)

Answer 1

Answer:

The value of a.b is -34.

Step-by-step explanation:

Since, the dot product of two vectors $A(a_1,a_2)$ and $B(b_1,b_2)$ is,

$A.B=a_1b_1+a_2b_2$

Given vectors,

a=(2,-8) and b=(-1,4),

Thus,  the dot product of vectors a and b,

$a.b = 2 \times (-1) + (-8)\times (4) = -2 - 32 = - 34$

Answer 2

a = negative 16 and b = negative 4