Find the angle between the vectors. (First find an exact expression and then approximate to the nearest degree.) a = <5, 4> , b = <2, −1>

Answer 1

come on, basic stuff
a dot b = |a| |b|cosØ, where Ø is the angle between them
<5, 4>dot<2, −1> = √(25+16)√(4+1)cosØ
10 - 4 = √205cosØ
cosØ = 6/√205
Ø = appr 65.2°