Tuesday

September 2, 2014

September 2, 2014

Posted by **Fredrick E.** on Tuesday, November 1, 2011 at 2:35pm.

I know that you have to find the derivative when it equals -1

i got

y'=(2x*y^2-y)/(2x^2*y+x)

(i don't know if it is correct or not)

but i don't know how to go from here. any help would be good

Thanks

- calculus -
**bobpursley**, Tuesday, November 1, 2011 at 3:21pmtry changing variables. let z=xy in the origianal equation, solve for z

z^2+z-2=0

(z+2)(z-1)=0

z=1 or -2 or z is a constant.

Then z=xy or

z'=y+xy'=0

but y'=1

y=-x and xy=-1 or 1

xy=-x^2

-2=-x^2

x=sqrt2, y=-x =-sqrt2

check: original line 4-2=2 checks.

1=-x^2

x=i, y=-x=-i

check: originalline 1=1=2 checks.

solutions:

pointA: x=i,y=-1

PointB: x=sqrt2, y=-sqrt2

- calculus -
**Anonymous**, Tuesday, November 1, 2011 at 6:44pmCan you explain using implicit differention?

- calculus -
**bobpursley**, Tuesday, November 1, 2011 at 10:07pmNo, I tried it that way, it bogged down in a third degree equation after I substituted, so I gave up that way.

**Answer this Question**

**Related Questions**

calculus - find all points on the curve x^2y^2+xy=2 where the slope of the ...

Calculus - Tangent Line - Hi, im having problems with the following problem. The...

Calculus - Consider the curve y^2+xy+x^2=15. What is dy/dx? Find the two points ...

Calculus - Consider the curve given by y^2 = 2+xy (a) show that dy/dx= y/(2y-x...

Calculus - I have a two part question that pertains to a curve (r(x)) and its ...

calculus - 1. Given the curve a. Find an expression for the slope of the curve ...

12th Grade Calculus - 1. a.) Find an equation for the line perpendicular to the ...

calculus - Find all points on the curve x^2y^2+xy=2 where the slope of tangent ...

Ap Calc AB - Find the equation of the line tangent to the curve at (5, -3) (x-2...

Calculus - the curve: (x)(y^2)-(x^3)(y)=6 (dy/dx)=(3(x^2)y-(y^2))/(2xy-(x^3)) a...