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If x=f(t )cost-f^(prime)(t)sinta n dy=f...

If x=`f(t )cost-f^(prime)(t)sinta n dy=f(t)sint+f^(prime)(t)cost ,t h e n((dx)/(dt))^2+((dy)/(dt))^2` (a) `f(t)-f^(primeprime)(t)` (b) `{f(t)-f^(primeprime)(t)}^2` (c) `{f(t)+f^(primeprime)(t)}^2` (d) none of these

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Given,`x= f(t) cost - f'(t) sint`
` y = f(t) sint + f'(t) cost `
`(dx)/(dt)=f′(t)cost−f(t)sint−f′′(t)sint−f′(t)cost`
= `-f(t) sint - f''(t) sint `
=` -sint[f(t) + f''(t)] `
`dy/dt=f′(t)sint−f(t)cost−f′′(t)sint−f′(t)sint `
=` -f(t) cost - f''(t) cost `
= `cost[f(t) + f''(t)]`
...
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