h(t)=(t-1)^2-(t+1)^2
0=(t-1)^2-(t+1)^2
(t+1)^2=(t-1)^2
t^2+2t+1=t^2-2t+1
2t+1=-2t+1
4t+1=1
4t=0
t=0
There is one zero at t=0
