# Vector and magnitude

1. Oct 6, 2008

### MarXphysics

1.I only need to know how to get magnitude out of a vector

2. Suchs as 25m = a cos (60 degrees)

3. I tried 25m/cos/60degrees but it don't seem right

please assist I know it isn't a real problem it's just the step that I need help. If you could write it in fomula form AX=A cos (theta) solving for "A". And if you can show me how to solve for "theta" as well please.

2. Oct 6, 2008

### granpa

magnitude is simply the length of the vector. if you are using cos then it sounds like what you really need is the x or y component.

3. Oct 6, 2008

### MarXphysics

I see that I may have been unclear Ax is the x component. I have Ax and I hav ethe angle theta what I do no thave is the magnitude.

4. Oct 6, 2008

### granpa

Ax is written A(sub)x(/sub) except that you use brackets.

5. Oct 6, 2008

### granpa

what do you mean solve for A??? thats trivial. A*cos(theta) is no different from A*B.

theta is a little harder. give me a minute.

6. Oct 6, 2008

### MarXphysics

Thanksyou
I have Ax = A cos $$\Theta$$
where I know Ax and $$\Theta$$
how do I find A

7. Oct 6, 2008