11) Найдите путь S, если v=2t–3(м/c) и при t=5, S=2
2=52–3·5+c ⇒ c=–8
S= 2t2/2–3t–8
∫ 30dx/(9+x2)=(1/3)arctg(x/3) |30=
=(1/3)arctg(1)–(1/3)arctg 0=(1/3)·(π/4)= π/12
11.
S(t)= ∫ v(t)dt= ∫ (2t–3)dt= ∫ 2tdt– ∫ 3dt=2·(t2/2)–3·t+C=t2–3t+C
при t=5; S(5)=2
2=52–3·5+C
2=25–15+C
С=–8
О т в е т.
S(t)=t2–3t–8 (м)