Question

Help with vectors

Answer 1

Which of the following is a vector that has a direction angle of θ = 77° and a magnitude of 4/7 ? Round your answer to the nearest tenth.

Answer 2

tan(77)=4.33147587

Answer 3

(0.1, -0.6)

(0.6, 0.1)

(0.1, 0.6)

(-0.6, 0.1)

Answer 4

this means that both points have to be positive

Answer 5

so that eliminates a and d

Answer 6

actually you would have to find the magnitude then multiply it by cos77 to find x and sin77 to find y

Answer 7

hint:

we have to request that:
\[\arctan \left( {\frac{y}{x}} \right) = 77^\circ \]

Answer 8

@Michele_Laino The closest I got to was 80 and that was arcsin(.6/.1)

Answer 9

I know it, I have computed that before

Answer 10

what am i doing wrong :/

Answer 11

if we consider the other case we have:
\[\theta = \arctan \left( {1/6} \right) \ne 77^\circ \]

Answer 12

That is true, but we are dealing with .1 and .6 :s

Answer 13

@amistre64

Answer 14

The answer is .1, .6 because 4/7cos77 and 4/7sin77