Question

if x=a(t-sint) , y= a(1-cost) dydx ?​

Answer 1

Answer:

dydx=dydtdxdt

Since, x=a(t+sint)

⟹dxdt=a(1+cost)

And y=a(1−cost)

⟹dydt=a[0−(−sint)]=asint

Therefore,

dydx=asinta(1+cost)=2sint2 cost22cos2 t2

=tan(t2)

Thus our first answer:

dydx=tan(t2)

Now for the second

d2ydx2=ddx(dydx)

Thus,

d2ydx2=sec2 (t2)⋅12⋅dtdx

Since,

dtdx=1dxdt=1a(1+cost)

Therefore,

d2ydx2=12sec2(t2)1a(1+cost)

d2ydx2=sec2 t22a⋅2cos2 t2

Hence the final result,

d2ydx2=sec4 t24a