Find the values of a and b if the The Slope of the tangent to the curve xy + ax + by = 2 at (1, 1) is 2.

Given:


The Slope of the tangent to the curve xy + ax + by = 2 at (1,1) is 2


First, we will find The Slope of tangent


we use product rule here,


(UV) = U + V


xy + ax + by = 2


x(y) + y(x) + a(x) + b(y) + = (2)


x + y + a + b = 0


(x + b) + y + a = 0


(x + b) = – (a + y)



since, The Slope of the tangent to the curve xy + ax + by = 2 at (1,1) is 2


i.e, = 2


{}(x = 1,y = 1) = 2


= 2


– a – 1 = 2(1 + b)


– a – 1 = 2 + 2b


a + 2b = – 3 ...(1)


Also, the point (1,1) lies on the curve xy + ax + by = 2,we have


11 + a1 + b1 = 2


1 + a + b = 2


a + b = 1 ...(2)


from (1) & (2),we get



substitute b = – 4 in a + b = 1


a – 4 = 1


a = 5


So the value of a = 5 & b = – 4


2