# Parametric Equations help!Watch

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#1
Hi, please could someone help, this is a one mark part of a question from parametric integration. I think im being really silly here but cant work out how they got this answer - its probably so obvious haha

theres a diagramm showing the curve c with parametric equations x=3t^2 and y=sin2t where t is greater than or equal to 0.

write down the value of t at the point a where the curve crosses the x axis (so basically on the diagram theres a curve and a is where it crosses the x axis)

thank you!!
0
4 weeks ago
#2
(Original post by TaySwiftie13)
Hi, please could someone help, this is a one mark part of a question from parametric integration. I think im being really silly here but cant work out how they got this answer - its probably so obvious haha

theres a diagramm showing the curve c with parametric equations x=3t^2 and y=sin2t where t is greater than or equal to 0.

write down the value of t at the point a where the curve crosses the x axis (so basically on the diagram theres a curve and a is where it crosses the x axis)

thank you!!
A curve crosses the x-axis when y=0 so just set y to 0 and solve the equation. If youâ€™re still stuck please post all your working.
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#3
hi thanks for you reply, I did that so I got sin2t=0 then I did sin^-1(0) on calculator and that gave me 0!
0
4 weeks ago
#4
(Original post by TaySwiftie13)
hi thanks for you reply, I did that so I got sin2t=0 then I did sin^-1(0) on calculator and that gave me 0!
The graph does the cross the x-axis at t = 0 but I'm assuming your question wants the positive solution? If you're not sure please post the whole question.

I'm sure you're aware that there are infinitely many solutions to and your calculator only gives you one value.
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#5
yes im aware of that, so how would you know you were looking for the next value?
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4 weeks ago
#6
(Original post by TaySwiftie13)
yes im aware of that, so how would you know you were looking for the next value?
Can you please post a picture of the question?
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4 weeks ago
#7
post a picture of the question
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