# calculus

what is the 2nd derivative of:
1-xy = x-y

i get (-y-1)/(x-1) for the first

the second i know is (-y-1)/(x-1)^2 but i keep getting (0)/(x-1)^2

please show me the steps i should be taking and if possible what i did wrong

1. 👍 0
2. 👎 0
3. 👁 79
1. I would solve it for y first

1-xy = x-y
y - xy = x-1
y(1 - x) = x-1
y = (x-1)/(1-x) = -1 , x ≠1

Well, isn't that special !!!

so y' = 0 and of course
y '' = 0

Wolfram took it as a pair of intersecting lines.
Notice the horizontal line y = -1
The vertical line x = 1 will give us y = any real number
e.g. (1, 4.56) will work
LS = 1 - 1(4.56)
RS = 1 - 4.56
LS = RS

http://www.wolframalpha.com/input/?i=plot+1-xy+%3D+x-y+

1. 👍 0
2. 👎 0
posted by Reiny

## Similar Questions

1. ### Calculus (Help)

Also I would like to know how to set this problem up in finding the answer: Find the second derivative. y= sqrt(3x+4) Thanks, P.S. I tried taking 3x+4 and squaring it to the 1/2. I thought that might've been the same, then I took

asked by Confused on February 21, 2007
2. ### Math

Find the intervals on which the function is increasing, decreasing, concave up, or concave down and find any local extreme values and inflection points. So I know how to do the above, but not with piece wise functions. Someone

asked by Beth on February 3, 2016
3. ### Math

Hi! im looking to find relationships between sets of polygonal numbers. I have found a few through the use of finite differences, (a relationship occurs between the formula to determine the polygonal number). I have also found

asked by Bob on October 14, 2008
4. ### Calculus

f(x)=[3x^13]e^(−7x) On which intervals is the function concave up and concave down? I know when you find the 2nd derivative, the x-values are 0, 1.34206, and 2.37222, and that the 2nd derivative > 0 at x=1.34205 and < 0 at

asked by Ann on May 18, 2014
5. ### Quantum mechanics, eigenfunctions!

Determine if the function sin(x)*e^(ax) where a=constant is an eigenfunction of the operators d/dx and d^2/(dx)^2 Okay. My understanding is that you use the operator and perform its "thing" on the function. In this case, you will

asked by Steven on October 8, 2009
6. ### Calculus

After t hours of an 8-hour trip the distance a car travels is modeled by: D(t)= 10t + (5)/(1+t) - 5 where D(t) is measured in meters. a) derive a formula for the velocity of the car. b) how fast is the car moving at 6 hours? c)

asked by Aletha on March 18, 2007
7. ### derivative

find the 2nd derivative of x+y = xy here is what I have so far: 1+dy/dx = x (dy/dx) + y

asked by Anonymous on November 14, 2018
8. ### derivatives

How do I find the 2nd derivative of x^(-1/15)

asked by Jacob on November 4, 2011
9. ### Calculus

2nd derivative of 3t^2 Cos(4t)

asked by Anonymous on March 17, 2010
10. ### Calculus--> bobpursley

How do you get m=0? from taking the second derivative? does c=1? Can you check my work on how I get the derivative of R=M^2(c/2-m/3) NEXT R=1/2(CM^2)-1/3(M^3) NEXT dR/dM=CM-M^2. I checked in the back, and that was the answer for

asked by Anonymous on May 30, 2007
11. ### Math

Whats the 2nd derivative of 4xsecx I got 4secxtanx+8xsecxtan^2x

asked by Edward on November 11, 2014

More Similar Questions