need some math help

[daschewy]

If any of you here have taken multivariable calculus (particularly vector calculus) I need some help with a problem.

I know how to do it in general, from what I remember, you just take the partial derivative with respect to X, and plugin the X value, and then do the same for Y (of course you have to set the equation equal to Z). The general equation should be i + Ck for the tangent line in the X direction and j + Ck in the Y direction.

 

[[5.SS]Strother]

2+2=4, thats about all of my knowledge of math

 

[Tomcat_ha]

I dont know what those terms are in dutch otherwise i could maybe help.

 

[-SemperFi-Jenova]

all i know is that i am glad i never took that class.

 

[daschewy]

I think I may have solved it out, Im assuming you'd want to find any general tangent lines, in both the X and Y direction. If so then it'd just be i + (1/y)k in the x-tangent, and j - (x/y^2)k.

Anyways, If you take the partial to both X and Y you'd end up getting 1/0 and 0/0 both which are undefined quantities. Id say carry out L' Hospitals rule but I dont think you can do it in this case, though if you could you'd end up getting 0 which would work out nicely because then the tangent lines would be i and j, though if you did the cross product you'd just get k, since it is the line that is perpendicular to both planes, but it wouldnt make much sense, since the graph of x/y is conic.

Anyways if I get the answer tomorrow Ill scan it up, in case anyone cares to see how to do it.

 

[CrazyThumbs]

Use calculus to find the Indentity of Batman:

 

[Coey]

Or you could just do that :/

 

[Athena]

Or you could just do that :/

rofl

 

[daschewy]

How would you solve this problem for a line in 2D, for example y = x^2 ?
You would find a derivative (2x) which is tangent (y/x) of the vector you are looking for in the given point x= p. You would compute the tangent and get 2p. Then you would compute your vector [x,y]: y = (2p)x (for some x), that is: [x,2px]. Then you would normalize it. Now exactly the same you have to do for x= yz. Only this time you have two lines - each time you assume that one coordinate is constant and compute derivative of the other (partial derivative). For each line solve the problem like you would do it for 2D. You will get 2 vectors. Compute their cross product and normalize the result.

P.S. your surface was defined as x = yz, I didn't understand why you are trying to express z through x and y.

P.P.S. there is probably some much easier and more elegant solution, but this is the first thing I could think of.

for the correct answer.

 

[=GG= Mr Moe]

I took enough of all the Calculus' in college. Enough!

The power of Christ compels you... The power of Christ compels you!

 

[daschewy]

or the power of the differential equation compels you

 

[Lt_Kettch]

What would Jesus do? That...

 

[CrazyThumbs]

I think I'll have to do that in my physics class soon, since I don't know anything. But instead of an elephant in the way, it'll be grimace (that fat purple thing from mcdonalds)