- S' = 2t² - 10t + 1
S' = - 2t² + 10t - 1
<img src="https://tex.z-dn.net/?f=%20%5Cfrac%7BdS%7D%7Bdt%7D%20%3D%20-2%20t%5E%7B2%7D%20%2B10t%20-1" />
dS = ( - 2t² + 10t - 1)dt
∫ dS = ∫ ( - 2t² + 10t - 1)dt
S = - 2 ∫ t² dt + 10∫ t dt - ∫ dt
<img src="https://tex.z-dn.net/?f=S%20%3D%20%20%5Cfrac%7B-2%7D%7B3%7D%20%20t%5E%7B3%7D%20%2B%205%20t%5E%7B2%7D%20-%20t%20%2B%20C" />
Si S(0) = 3 entonces
t = 0 y S = 3
3 = 0 + 0 + 0 + C
→ C = 3
∴<img src="https://tex.z-dn.net/?f=S%20%3D%20-%20%5Cfrac%7B2%7D%7B3%7D%20%20t%5E%7B3%7D%20%2B%205%20t%5E%7B2%7D%20-%20t%20%2B%203" />.