Question

Consider the vector v = (-7, 8)

Part 1.

Use the formula v1 * v2 = |v1||v2|cosθ to find the cosine of the angle between the two vectors (-7, 8) and (1, 10).

(-7+8j)(1+0j) = |sqrt(-7^2+8^2)||1|cosθ
-7 = sqrt(113) cosθ
cosθ = -6.59

Was that right?

Part 2.

Use the cosine of the angle to find the actual angle between the two vectors.