question_answer

A point on the parabola\[{{y}^{2}}=18x\]at which the ordinate increases at twice the rate of the abscissa, is

A) (2, 4)                     

B) (2, -4)   

C)        \[\left( -\frac{9}{8},\frac{9}{2} \right)\]        

D)        \[\left( \frac{9}{8},\frac{9}{2} \right)\]

Correct Answer: D

Solution :

Equation of parabola is. On differentiating w.r.t. t, we get                         From equation of parabola,                               Hence, point on parabola is.