1.

If`M(x_o,y_o)` is the point on the curve `3x^2-4y^2=72` which is nearest to the line `3x+2y+1=0`, then the value of `(x_o + y_o)` is equal to (A) 3 (B) `-3` (C) 9 (D) `-9`

Answer» `3x^2-4y^2=72`
`m=-3/2`
`6x-8y(dy)/(dx)=0`
`(dy)/(dx)=(3x)/(4y)`
`(3x_0)/(4y_0)=-3/2`
`x_o=-2y_o`
`8y_o^2=72`
`y=pm3`
`3x+2y+1=0`
`3x+2y+c=0`
`c=-3x_0-2y_o`
`|c-1| is minimum=4y_0`
|c-1| is minimum at` c=12 andy_o=3`
`x_0+y_0=3+3*(-2)=-3`
option b is correct.


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