Originally Posted by

**KarlosK** I have 2 questions:

The first says: find an equation for the line tangent to the ccurve at the point defined by the given value of t. Also find the value of d^2y/dx^2.

x= t y= sq root(t) t= 1/4

(I am not sure how to do this problem so an explanation would be great)

Also I have a question that says: The position of a particle moving along a coordinate line is s= sq root (1+4t) with s in meters and t inseconds. Find the particles velocity and acceleration at t=6

For this problem I just found the derivative which is

(1/2(1+4t)^-1/2) x (4t) and I got an answer of 6 for the velocity and the back of my book has 2/5 as the answer. What am I doing wrong?