Prove parametric equations trochoid
take a hard look at picture take some fixed point anywhere on the circle and when the circle is rolled around the curve drawn by the the fixed point is the TROCHOID
in the diagram i have drawn i labelled it as point D some where on circle also i have taken the angle to be "a"
from the diagram you can see that point D is online CP and P started initially from origin and it has travelled by an angle of "a" so PR=OR= ra ( PCR is a sector with angle a and arc length ra)
our job is to find the x and y coordinates of D which is making the curve
from triangle CDQ
CD=d which is given in our question
CQ= d $cosa$ and DQ= d $sina$
now xcoordinate of point D= OR DQ
SO x= r*ad $sina$
and y coordinate of point D = CR QR
y=r d $cosa$
hence the parametric representation of the curve is
x= r*ad $sina$
y=r d $cosa$
Related videos on Youtube
Sam Creamer
Updated on August 01, 2022Comments

Sam Creamer 1 day
I have to show that the parametric equations of a trochoid are:
$x = r\theta  d\sin\theta$ and $y=rd\cos\theta$
where r is radius and d is the distance between center of the circle and a point P.
Can someone please explain this to me? I'm in my second week of advanced Calculus, thanks

Spine Feast almost 9 yearsen.wikipedia.org/wiki/Trochoid has a reasonable derivation, have you studied it?

Sam Creamer almost 9 yearsnot really... it was just thrown at me and I had never seen it before and I don't think I fully understand it


Mr. Math almost 9 yearsmy pleasure hope it helps