y=-2t²+5t-2 求t

y=-2t²+5t-2 求t
y=-2t²+5t-2 求t

y=-2t²+5t-2 求t
是y=0?
-2t²+5t-2=0
2t²-5t+2=0
(2t-1)(t-2)=0
t=1/2,t=2

y=-2t²+5t-2 求t
2t²-5t+y+2=0，故t={5±√[25-8(y+2)]}/4=[5±√(9-8y)]/4，y≦9/8.