slope of a tangent

[jbknudsen]

Howdy to all. we are working on a problem that involves finding the slope of a tangent to a curve. Myself and a few other are arriving with consistant answers, however, our answers are not correct.
Q: Find the slope of a tangent to the curve of
y=ln(25x + 3) at x=2.

Running the natural log as "y", we continue to get an answer of 3.9703 for the value of x=2.

Any clues on what we are doing wrong.

Thanks,
Jay

 

[dford]

JB:

(1/u)(du/dx)|2 = 25/53

Doug

 

[IRstuff]

using the chain rule, the derivative should be:
25/(25x+3). Evaluated at x=2, I get a slope of 0.4717

TTFN

 

[jbknudsen]

Thanks to you both, much appreciated.

 

[solidworkswell]

take the derivative of the equation with repect to "x" and then plug in "x=2" with resultant equation. that should be your slope of the line.