# Math Help - Calculating Flow Lines

1. ## Calculating Flow Lines

I tried figuring it out from the book, but I'm not able to.

Calculate the flow line x(t) of the given vector F that passes through the indicated point at the specified value of t.
F(x,y)= -xi + yj; x(0)=(2,1)

I'd really appreciate help! Thanks so much.

2. ## Re: Calculating Flow Lines

Originally Posted by JennaIsbell
I tried figuring it out from the book, but I'm not able to.

Calculate the flow line x(t) of the given vector F that passes through the indicated point at the specified value of t.
F(x,y)= -xi + yj; x(0)=(2,1)

I'd really appreciate help! Thanks so much.
Hi JennaIsbell!

The function x(t) consists of two functions x(t) and y(t). That is, x(t) = x(t)i + y(t)j.
At any point its derivative needs to match F(x,y).
So F(x(t),y(t)) = x'(t)i + y'(t)j.

Can you solve that?