- #1

- 185

- 2

## Homework Statement

Consider the vector r(t)= (1-t)i + (3+2t)j + (t-4)k which depends on scalar parameter t. For which t

_{0}is the length of r(t

_{0}) minimal?

## Homework Equations

Equations of motion

## The Attempt at a Solution

So I approached this question by saying the length would be minimal when the magnitude is minimal ie. |r|=0.

|r|=√[(1-t)

^{2}+(3+2t)

^{2}+(t-4)

^{2}]

Simplified down I got 3t

^{2}+t+13=0

I tried using the quadratic formula to solve this then but couldn't as the value under the square root was negative.

Am I approaching this question wrong then? Any help would be much appreciated.