Question #0c4d4

1 Answer
Dec 22, 2017

color(blue)(f(t) = -4sqrt(t)+Ct+D)

Explanation:

We are given the second derivative of f(t)

color(red)(f''(t) = t^(-3/2))

That is, color(red)((d^2y)/(dt^2) = t^(-3/2))

We must find color(blue)(f(t) using the given details.

Solution Process being used:

We will integrate color(red)(f''(t) = t^(-3/2)) to obtain the first derivative of f(t) and get color(blue)(f'(t)

Then we will integrate color(blue)(f'(t) to obtain color(blue)(f(t)

color(green)(Step.1)

To find the first derivative, we integrate color(red)(f''(t)

Hence, color(red)(f'(t) = int " " f''(t)*dt

f'(t) = int " "t ^ (-3/2)*dt

rArr t ^ (-3/2+1)/(-3/2+1)+C

rArr t^(-1/2)/(-1/2)+C

rArr -t^(-1/2)/(1/2)+C

rArr -2t^(-1/2)+C

rArr -2/sqrt(t)+C

color(blue)(f'(t) = int " "t ^ (-3/2)*dt = -2/sqrt(t)+C)

That is, color(red)((dy)/(dt) = -2/sqrt(t)+C)

color(green)(Step.2)

To obtain the f(t), we integrate color(red)(f'(t)

Hence, color(red)(f(t) = int " " f'(t)*dt

We will now work on

color(red)(f(t) = int " " f'(t)*dt =int " " -2/sqrt(t)+C *dt

We will pull the constant term out to get

-2int " " 1/sqrt(t)+C*dt

rArr -2 int t ^ (-1/2)+C* dt

rArr -2.[t^(-1/2+1]/(-1/2+1]]+(C/1)*t^1

rArr -2.[t^(1/2]/(1/2]]+Ct

rArr -2.(2/1)*[t^(1/2)]+Ct

rArr -4.sqrt(t)+Ct

We must also add a constant term to our answer.

Hence,

color(blue)(f(t) = -4sqrt(t)+Ct+D)

is our required function