Posted by **Leah** on Wednesday, May 15, 2013 at 12:17pm.

Calculate d/dt when a=t^2, b=2 and sqrt(x+1)dx.

My answer turns out to be incorrect despite my checking it several times. I got -2/3t* sqrt(t^2+1)

Can someone explain to me what is wrong with my answer and how to go about obtaining it the right way? Thank you everyone. :-)

- D/dt -
**Steve**, Wednesday, May 15, 2013 at 2:54pm
f(t) = ∫[2,t^2] √(x+1) dx

df/dt = √(t^2+1) (2t)

Recall that d/dt ∫[a,b(t)] f(x) dx = f(b(t)) db/dt

see wikipedia's article on differentiating under the integral sign.

- D/dt -
**Leah**, Wednesday, May 15, 2013 at 5:02pm
Thank you for the equation and the useful article. :)

So this is what I get.

f(t) dt= 2(0)- [sqrt(t^2+1) * 2t]

f(t) dt= -sqrt(t^2+1) *2t

Is this correct? Thank you so much. :-)

## Answer this Question

## Related Questions

- Calculus - Please look at my work below: Solve the initial-value problem. y'' + ...
- MATH - I need to simply this equation, but I got stuck. h/(4-sqrt(16+h)) = y ...
- Calculus - Second Order Differential Equations - Solve the initial-value problem...
- Calculus - Second Order Differential Equations - Posted by COFFEE on Monday, ...
- Calculus (Checking Answer) - Find the antiderivative by hand in each case. S ...
- Calc. Checking Answer - Find the antiderivative by hand in each case. S stands ...
- Math Help please!! - Could someone show me how to solve these problems step by ...
- Calculus - Evaluate the indefinite integral: 8x-x^2. I got this but I the ...
- Math/Calculus - Solve the initial-value problem. Am I using the wrong value for ...
- Algebra - How do you simplify this? -16^(1/4) Someone showed me like this: (-1)(...