Finding coordinates given vector eqns and point

**Tutu** · February 15th 2013, 11:14 PM

How do I do this,

Point A(3,0,-2) lies on the line r=3i-2k+ t(2i-2j+k) where t is a real parameter. FInd the coordinates of one point which is 6 units from A, and on the line.

I put the equation of the line to parametric form and then, subtracted A from these parametric equations.. but I dont know what I am doing really.

THank you so much!

**chiro** · February 16th 2013, 01:26 AM

Hey Tutu.

Hint: Try getting your line in terms of L(t) = a + n*t where n is a unit vector with length 1 and a is your starting point you are starting from and note that for some value t, it will be exactly t units in the direction of n from a.

**Tutu** · February 16th 2013, 02:38 AM

Thanks but isn't it already in terms of a+N*t with r=3i-2k + t(2i-2j+k)?

**Plato** · February 16th 2013, 04:05 AM

Originally Posted by Tutu

Point A(3,0,-2) lies on the line r=3i-2k+ t(2i-2j+k) where t is a real parameter. FInd the coordinates of one point which is 6 units from A, and on the line.