Vectors A and B lie in an xy plane. A has magnitude 7.60 and angle 134° from the positive direction of the x axis. B has components Bx = 7.84 and By = -9.20. (Type 'undefined' for any answer if appropriate.)
(a) What is 3A·B?

(b) What is 4A 3B in unit-vector notation?
k
(c) What is 4A 3B in magnitude-angle notation with spherical coordinates (see Fig. 3-36)?

Fig. 3-36
, θ = °, = °
(d) What is the angle between the directions of A and 4A 3B? (Hint: Think a bit before you resort to a calculation.)
°
(e) What is A + 6.00 k in unit-vector notation?
i + j + k
(f) What is A

Question

Vectors A and B lie in an xy plane. A has magnitude 7.60 and angle 134° from the positive direction of the x axis. B has components Bx = 7.84 and By = -9.20. (Type 'undefined' for any answer if appropriate.)
(a) What is 3A·B?
 
(b) What is 4A  3B in unit-vector notation?
  k
(c) What is 4A  3B in magnitude-angle notation with spherical coordinates (see Fig. 3-36)?

Fig. 3-36
 , θ =  °,   =  °
(d) What is the angle between the directions of A and 4A  3B? (Hint: Think a bit before you resort to a calculation.)
 °
(e) What is A + 6.00 k in unit-vector notation?
  i +   j +   k
(f) What is A

anonymous · Answer

I believe you may be missing some symbols for part b and c.

(a) 3A = (3x7.60 cos(134 ), 3x7.60 sin(134)) = (-15.83, 16.40)
B = (7.84, -9.20)

3A · B = -15.83 x 7.84 + 16.40 * -9.20 = -274.99