S(t) = 4t³ - 5t
V(t) = S'(t) = (4t³ - 5t)' = 4(t³)' - 5(t)' = 12t² - 5
V(t) = 2
12t² - 5 = 2
12t² = 7
t² = 7/12
S(t)=4t³-5t
V(t)=S'(t)=12t²-5
12t²-5=2
12t²=7
t²=7/12
t=√(7/12)=√(7/(4*3))=1/2 * √(7/3) - это ответ. t>0
S(t) = 4t³ - 5t
V(t) = S'(t) = (4t³ - 5t)' = 4(t³)' - 5(t)' = 12t² - 5
V(t) = 2
12t² - 5 = 2
12t² = 7
t² = 7/12
S(t)=4t³-5t
V(t)=S'(t)=12t²-5
12t²-5=2
12t²=7
t²=7/12
t=√(7/12)=√(7/(4*3))=1/2 * √(7/3) - это ответ. t>0