A = –1i + 3j
Solve tan(θ) = 3/1. This will solve for the angle in the slope triangle for A.
Recall that the standard angle is measured from the positive x-axis.
A + B = 〈 –1, 3〉 + 〈 4, 3〉 = ?
The double bars mean "the magnitude of". To calculate the magnitude of vector B, use the Pythagorean Theorem.