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Homework Statement
A curce has equation:
x² + 2xy - 3y² + 16 = 0
find the co-ordinates of the points on the curve where dy/dx = 0
Homework Equations
The Attempt at a Solution
I dont have a clue. Do I convert them into parametric equations?
i tried looking at implicit differentiation here http://www.maths.abdn.ac.uk/~igc/tch/ma1002/diff/node49.html
and my book but i dont understand it.
dy/dx (x² + 2xy - 3y² + 16)
= 2x + 2y - 3y² + 16
Apparently i should use the chain rule somewhere?
Thanks
dy/dx = dy/du x du/dx is the chain rule. What is u and y
im still lost completely. I know the chain rule. I dont see how y is 3y² nor why u is y. Can you show me why. Why do you set u equal to y?
Thanks :)
is d/dx of 2xy
= 2(x+y)
= 2x + 2y ???
i don't think it is. I've used the product rule (dy/dx = v du/dx + u dv/dx).
NOTE is it 2y + 2x . (dy/dx) or 2y . (dy/dx) + 2x
find the co-ordinates of the points on the curve where dy/dx = 0
ahhh YOU ACUTLALY SUBST FOR dy/dx = 0
2x + 2y = 0
y = x
please say that is right...
Thanks :)
Night Night.
ahhh YOU ACUTLALY SUBST FOR dy/dx = 0
2x + 2y = 0
y = x
please say that is right...
Thanks :)
Night Night.
x = +-2
SOOOOOOOO ill sub x = - y
y² - 2y² - 3y² = 0