i got a problem solving this Diff. system with initial value problem 2nd order.

$$ y''\_1=−10y\_1+6y\_2 $$

$$y''\_2=6y\_1−10y\_2$$

$$y\_1(0)=1,y\_2(0)=0,y\_1'(0)=0,y\_2'(0)=0 $$

i need the value for: $$ y\_2(\pi/2)= ? $$

according my math script, i got 2 different values and i dont know which one is right or both wrong.
my values are: $-1$ and $0$

I hope someone can tell me which one is right or if both are wrong which value would be right, so i can look over and try to find my mistake.

Thx.