# Thread: Deriv help. Some of these problems kill me.

1. ## Deriv help. Some of these problems kill me.

g(t)= at^2+bt+c; g(1)= 5; g'(1)= 3; g"(1)= -4. Find a,b,c. I don't even know where to start. I know how to take the derivative and the 2nd, 3rd, 4th etc. But what am I suppose to do here.

2. ## Re: Deriv help. Some of these problems kill me.

$g(t) = at^2+bt+c$

$g'(t) = 2at + b$

$g''(t) = 2a$

from the given info for the three function vales at $t = 1$ ...

$5 = a+b+c$

$3 = 2a + b$

$-4 = 2a$

solve the system ...