Задача 33661 ...

sova

2019-02-17 18:14:33

★

2,25+8t-4t^2 >4

4t^2-8t + (7/4) < 0

4t^2-8t+(7/4)=0

t^2-2t+(7/16)=0

D=4-4*(7/16)=(64-28)/16=36/16
t_(1)=(2-(6/4))/2=1/4; t_(2)=(2+(6/4))/2=7/4

t_(2) - t_(1)=(7/4) - (1/4)=6/4=3/2=1,5 секунды