The displacement of a body is given by `r=sqrt(a^(2)-t^(2))+t cost^(2)` , where `t` is the time and a is constant. Its velosity is `:`

Options

A. `(-t)/(sqrt(a^(2)-t^(2)))+cos t^(2)-t sin 2t`
B. `(-t)/(sqrt(a^(2)-t^(2)))+cos t^(2)-2t^(2) sin 2t^(2)`
C. `(-a)/((a^(2)-t^(2)))+2 t cos t^(2) sin t+sin t`
D. `a -t^(2)- t sin t^(2)`

Answer

B

Explanation

`r= sqrt(a^(2)-t^(2))+t cos t_(2)`
`V=(dr)/(dt)=(1)/(2)(a_(2)-t_(2))-1//2 (-2t)+t(-sin t_(2))2t_(1)+ cos t_(2)`
`V=-(t)/(sqrt(a^(2)-t^(2)))-3 t_(2) sin t_(2) +cos t_(2)`.