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C4 Question Help

x= sint + t, y= sint,

a) find dy/dx in terms of t.b) Find, in exact form, the coordinates of the point where thetangent to the curve is parallel to the x-axisc) Show thatthe region bounded by the curve and the x-axis has area 2.

I have done part a) and got the answer of cost/(1+cost) which I know is correct. I don't know how you do part b) and c) as there are no co-ordinates give. The curves touches the x-axis at 0 and another unlabelled point.
(edited 8 years ago)
@Improvement, please edit your OP :h:
Reply 2
Original post by Kvothe the arcane
@Improvement, please edit your OP :h:


Just done it.
Original post by Improvement
x= sint + t, y= sint,

a) find dy/dx in terms of t.


I have done part a) and got the answer of cost/(1+cost) which I know is correct. I don't know how you do part b) and c) as there are no co-ordinates give. The curves touches the x-axis at 0 and another unlabelled point.

The tangent to the curve is parallel to the x axis when there is no gain in y, ie when dy/dx=0.
Reply 4
Original post by Kvothe the arcane
The tangent to the curve is parallel to the x axis when there is no gain in y, ie when dy/dx=0.


so it will be the TP co-ordinate of the curve? so I would make cos(t)/1+cost = 0?
so cos(t) =0?
Reply 5
Got the answer to b) only need to do c now
Original post by Improvement
so it will be the TP co-ordinate of the curve? so I would make cos(t)/1+cost = 0?
so cos(t) =0?


Indeed
Original post by Improvement
Got the answer to b) only need to do c now


Was there an image of the graph or a range?
Reply 8
Original post by Kvothe the arcane
Was there an image of the graph or a range?


It is in the positive quadrant of the graph and comes from the origin to an unmarked point of the x-axis where it ends.
Original post by Improvement
It is in the positive quadrant of the graph and comes from the origin to an unmarked point of the x-axis where it ends.


Any chance you can upload an image?
Original post by Kvothe the arcane
Any chance you can upload an image?




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So the limits are 0 and pi (I might be wrong).

A=βαy dxdt dt\displaystyle A= \int^{\alpha}_{\beta}y \ \dfrac{dx}{dt} \ dt
(edited 8 years ago)
Reply 12
plain parametric integration
limits are correct
Original post by Kvothe the arcane
So the limits are 0 and pi (I might be wrong).

A=βαy dxdt dt\displaystyle A= \int^{\alpha}_{\beta}y \ \dfrac{dx}{dt} \ dt




I have y obviously as sint and dx/dt = 1+cost so before integrating should I multiple the brackets? or just keep them as they are?
Original post by Improvement


I have y obviously as sint and dx/dt = 1+cost so before integrating should I multiple the brackets? or just keep them as they are?

Well you do what you think you need to do to integrate.

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Original post by Kvothe the arcane
Well you do what you think you need to do to integrate.

Sent from my SM-G925F using Tapatalk


I got the answer :biggrin: thanks guys!
No worries @Improvement, I'm glad we were able to help.
Reply 17
Original post by Kvothe the arcane
No worries @Improvement, I'm glad we were able to help.


you called my Lord?

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