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C4 Mixed Exercise 2E Question 7b

Hey Everyone,

I am stuck on question 7b from C3 Mixed Exercise 2E as the title says.
The question is this,

7. A curve has the parametric equations, x = t2 - 1 , y = t - t3, where t is a parameter.
a. Draw the graph of the curve for -2 t 2
b. Find the area of the finite region enclosed by the loop.

So if you draw the graph you get thisScreen Shot 2016-01-22 at 18.02.13.png. So I know that the equation for the area would be: 4t2 - 4t4 however if yo do this for the boundaries of 0 and -1 you just get 0. In the solutions they have used 1 and 0 as the boundaries, but I don't get why? Can someone please explain this?
Reply 1
Original post by BenRichi_
Hey Everyone,

I am stuck on question 7b from C3 Mixed Exercise 2E as the title says.
The question is this,

7. A curve has the parametric equations, x = t2 - 1 , y = t - t3, where t is a parameter.
a. Draw the graph of the curve for -2 t 2
b. Find the area of the finite region enclosed by the loop.

So if you draw the graph you get thisScreen Shot 2016-01-22 at 18.02.13.png. So I know that the equation for the area would be: 4t2 - 4t4 however if yo do this for the boundaries of 0 and -1 you just get 0. In the solutions they have used 1 and 0 as the boundaries, but I don't get why? Can someone please explain this?


find the way the curve is traced.
determine the value of t at the node
that will be a start
Original post by BenRichi_
Hey Everyone,

I am stuck on question 7b from C3 Mixed Exercise 2E as the title says.
The question is this,

7. A curve has the parametric equations, x = t2 - 1 , y = t - t3, where t is a parameter.
a. Draw the graph of the curve for -2 t 2
b. Find the area of the finite region enclosed by the loop.

So if you draw the graph you get thisScreen Shot 2016-01-22 at 18.02.13.png. So I know that the equation for the area would be: 4t2 - 4t4 however if yo do this for the boundaries of 0 and -1 you just get 0. In the solutions they have used 1 and 0 as the boundaries, but I don't get why? Can someone please explain this?


You need to use the limits of t, not x.

Use the equation x = t2 - 1 to change your limits of 0 and -1 for x to the corresponding limits for t.
Reply 3
Original post by kingaaran
You need to use the limits of t, not x.

Use the equation x = t2 - 1 to change your limits of 0 and -1 for x to the corresponding limits for t.


Okay sure thing, thanks for your help I can use the limits 1 and 0 now. That makes so much sense!

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