Help? How did they know where theta was?
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Find the direction angle of the vector u = 8i + 5j.

We know that if v = ai + bj, then the direction angle is given by tan-1b/a . We also know theta is in Quadrant I. Thus,

tan(theta) = b/a = 5/8 = .625 → tan^-1(theta) = 32.01°

Question

Help? How did they know where theta was?
-->
Find the direction angle of the vector u = 8i + 5j.

We know that if v = ai + bj, then the direction angle is given by tan-1b/a . We also know theta is in Quadrant I. Thus,

tan(theta) = b/a = 5/8 = .625 → tan^-1(theta) = 32.01°

anonymous · Answer

ok? question solved

anonymous · Answer

I know the answer is there. Geez. I posted the question. But to answer these, apparently I'm supposed to immediately know where the theta is. How do you just know where theta is?

anonymous · Answer

depends on which quadrant the head of the vector points at.. In this case, it's quadrant I

anonymous · Answer

So I have to find the head of the vector? Would that be a or b or something?

anonymous · Answer

|dw:1393262500647:dw|

anonymous · Answer

(a,b) = (8,5), which is in quadrant 1

anonymous · Answer

Oh, so for this one, it is (8,5)? That makes so much more sense.

anonymous · Answer

yea

anonymous · Answer

Thank you so much. God bless you! :DDD