Thread: Components
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Old 05-10-2008, 06:58 AM
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TheEmptySet TheEmptySet is offline
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Quote:
Originally Posted by NAPA55 View Post
I'll just make something up, so when I do the actual problems I still have to think lol

- They give the coordinates of the tail
- They give the magnitude
- They say the vector is in the same direction as u = (4, -3, -6)

I guess by direction they mean which way it is is moving (on positive or negative axis)...

From my made up question here, x is a positive direction while y and z are negative, so I guess that means that the vector that I'm finding has to have a positive x value but negative y and z values.
Because I'm boring lets use the tail at (a,b,c)

So a vector with the same direction as (4,,-3,-6) passing through (a,b,c) can be written as

v=(a,b,c)+t(4,-3,-6)=(4t+a,-3t+b,-6t+c)


We can find the magnitude

\sqrt{(4t+a)^2+(-3t+b)^2+(-6t+c)^2}=M

From here plug in the magnitude for M and solve the quadratic for the value of t and sub back into the original equation.

Good luck.
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