Easy differential equation but i am stuck

[fufufu]

Homework Statement

What is the general solution of tv' + v = 0?
book says it is v(t) = c/t but i don't see how
i tried to solve like this:

v' + (1/t)v = 0

p(t) = 1/t
P(t) = Ln(t)

y = e^ln(t) + c

= t + e^c

please help,thanks

Homework Equations

The Attempt at a Solution

 

[lanedance]

what is y?

your first equation is separable, write v'=dv/dt, then move all terms with a v to the LHS and all terms with a t to the RHS then integrate both sides

 

[vela]

Homework Statement

What is the general solution of tv' + v = 0?
book says it is v(t) = c/t but i don't see how
i tried to solve like this:

v' + (1/t)v = 0

p(t) = 1/t
P(t) = Ln(t)

y = e^ln(t) + c

This isn't right. What you're doing by calculating $e^{\int p(t)\,dt}$ is finding an integrating factor, not the solution to the differential equation. Check your textbook to see what you're supposed to do with this factor.

(Or solve the problem the way lanedance suggested.)