# Vector problems

#### nhunhu9

I just started on vector and there are some confusing problems i want to ask:

Find the magnitude and direction angle of the vector:
1)$$\displaystyle 3i-4j$$<- on this one i found the magnitude but not the direction angle, though i'm positive that i did just like i've done with some previous problems. I got 53.13, but the answer in the book is 306.87

2)$$\displaystyle -3i-5j$$<-- i also got the magnitude of this one, but not the direction angle. again 3)$$\displaystyle 7(cos135i+sin135j)$$

Find the vector v with the given magnitude and the same direction as u
$$\displaystyle |v| = 1, u =<3,-3>$$

Last edited:

#### skeeter

MHF Helper
I just started on vector and there are some confusing problems i want to ask:

Find the magnitude and direction angle of the vector:
1)$$\displaystyle 3i-4j$$<- on this one i found the magnitude but not the direction angle, though i'm positive that i did just like i've done with some previous problems. I got 53.13, but the answer in the book is 306.87

+i , -j ... quadrant IV angle

2)$$\displaystyle -3i-5j$$<-- i also got the magnitude of this one, but not the direction angle. again -i , -j ... quadrant III angle

3)$$\displaystyle 7(cos135i+sin135j)$$

what is your problem with this vector?

Find the vector v with the given magnitude and the same direction as u
$$\displaystyle |v| = 1, u =<3,-3>$$

v = < 1/sqrt(2) , -1/sqrt(2) >
...

• nhunhu9

#### nhunhu9

Number 3 is also find the direction angle but since the fisrt and second problems have to do with quadrant i already firgured it out. Thank you

Similar Math Discussions Math Forum Date
Algebra
Pre-Calculus
Calculus
Geometry