Posted by **Eve ** on Tuesday, September 17, 2013 at 5:57pm.

Find the points on the graph of f where the tangent line is horizontal.

original: x/x^2+25)

After I did the quotient rule I got:

(x^2+25)(1)-(x)(2x)/((x^2+25))^2

Then of course I know you set that equal to 0, but I do not know how to set it up or "finalize" the problem because of the denominator. Please help!

- calculus (derivativs) -
**Graham**, Tuesday, September 17, 2013 at 6:08pm
((x^2+25)(1)-(x)(2x))/(x^2+25)^2 = 0

Simplify

(25-x^2)/(x^2+25)^2 = 0

As long as x^2+25 <> 0 then you can multiply both sides by the denominator

(25-x^2) = 0

Thus

x^2 = 25

x = ±5

( Check: 25+25<>0 .. okay)

Find y when x=-5 and x=+5. These are your points

- calculus (derivativs) -
**Eve **, Tuesday, September 17, 2013 at 6:10pm
does that go into the derivative equation or the original?

## Answer this Question

## Related Questions

- Calculus (derivatives) - Find the points on the graph of f where the tangent ...
- Calculus - 55. Find an equation of the tangent line to the graph of f(x) =x^3 - ...
- Calculus - Given the function y=(x^2-5/x+3), answer the following questions. a) ...
- math - question: find the points at which the graph of x^2 -4x + y62 -6y =12 has...
- calculus - find the points at which the graph of 4x^2 - 4x + 12y^2 -6y = 10 has ...
- cal - Determine all values of x, (if any), at which the graph of the function ...
- Calculus - The function g is defined for x>0 with g(1)=2, g'(x)=sin(x+1/x), ...
- Calculus - I have a two part question that pertains to a curve (r(x)) and its ...
- College Calculus - Let f(x) = 3x^2 - 2x + 1 a) write an equation of the line ...
- Calculus - Graph the function f(x)=x+4/x Graph the secant line that passes ...

More Related Questions