Problem manipulating solution of a differential equation

[the0]

Homework Statement

Y'(u) = A(u)Y(u)

V(u) is the general solution

The question asks to show that if A(u) is antisymetric for all u
i.e. ^{t}A(u) = -A(u) for all u
Then ^{t}V(u).V(u) = I

Homework Equations

A hint says to use the fact that V(0) = I

The Attempt at a Solution

Using the fact given in the hint I have a solution

(differentiate ^{t}V(u).V(u) and show that this is zero, therefore ^{t}V(u).V(u) is constant, and since the hint implies ^{t}V(0).V(0) = I the problem is solved)

HOWEVER, I do not understand why V(0) = I!
Maybe it's something obvious which I just cannot spot!
Please could somebody explain this to me

 

[dikmikkel]

V(0)=I because V(x) = K_1e^{\int A(x)\text{d}x}
i.e. every exp function with argument 0 is 1.
So you have to prove that it is the solution V(x) maybe?