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1. A curve is defined parametrically by x = (t^2 + 1) , y = t^3
Find (dy)/(dx) when t = 2

The chain rule: (dy/dx) = (dy/dt) x (dt/dx)
My calculation says that x = 5, y = 8
so (dy/dx) must equal 8/5 but the answet given is 3.
Can anybody help me?
2. you calculated y/x not (dy/dt) x (dt/dx)

Find dy/dx in terms of t and then replace
3. But (to me) i see dy/dx and just see that cancelling down into y/x? Finding in terms of t isnt helping me
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4. (Original post by pontifexmaximus)
But (to me) i see dy/dx and just see that cancelling down into y/x? Finding in terms of t isnt helping me
d/dx is an operator. You cannot cancel d from it to get 1/x

d/dx means differentiate wrt x.

d/dx (y) means differentiate y wrt x. This is written as dy/dx. You cannot simplify this to y/x.

Finding dy/dx in terms of t is helping you as you just replace t = 2 and get the gradient

Use chain rule dy/dx = dy/dt divided by dx/dt
5. ok well its clear to me that i dont have a clue lol my course book has just dropped this thing on me without teaching me any of this stuff beforehand lmao
thanks for the help
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