Given curve y=c/(x+1).. (1)
Its slope at any poit is dy/dx = -c/(x+1)^2 (2)
The slope and equation of the line joining (0,3) and (5,2) are
(2-3)/(5)= -(1/5) ....(3) and
y = -(1/5)x+3........(4).
At the tangent point the slope of line and the curve are same, therefore, from(3) and (2): -1/5=-c/(x+1)^2 ==>
5c=(x+1)^2.........(6)
Solving for the line and the curve, from rom ((4) and (1),
-(1/5)x +3 = c/(x+1)==>
5c=(-x+15)(x+1) = -x^2+14x+15.........(7)
Eliminatin c between (6) and (7) we get x cordinate of the tangent touching the curve :
(x+1)^2=-x^2+14x+15==>
x^2-12x-14=0==>
(x+1)(x-7)=0.
x=-1 and x=7. But x=-1 is a vertical asymptote.
Putting x=7 in Eq (6) gives 5c =(7+1)^2
5c=64
c = 64/5 =12.8.
The tangent touches curve at
the point. (7, 12/(7+1))=(7, 1.5)
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