MHT CET20239 May 2023Evening ShiftMathematicsApplication of DerivativesActual
If slope of a tangent to the curve x y+a x+b y=0 at the point (1,1) on it is 2 , then a-b is
Options
- A3
- B1
- C2
- D-1
Correct answer
A. 3
Step-by-step solution
Given curve is aligned & x y+ a x+ b y=0 & Slope =2= d y ~d x & x y+ a x+ b y=0 aligned Differentiating w.r.t. x , we get aligned & x d y ~d x +y+ a + b d y ~d x =0 & (x+ b ) d y ~d x =-(y+ a ) & d y ~d x = -(y+ a ) x+ b & ( d y ~d x )_ (1,1) =2 & 2= -(1+ a ) 1+ b & a +2 ~b =-3 ... (i) aligned Since (1,1) lies on x y+a x+b y=0 , we get a + b =-1 ... (ii) Solving (i), (ii), we get aligned & a=1, b=-2 & a-b=1-(-2)=3 aligned