The tagent to the curve y = 1+1/x is given by
.
y-y1 = (dy/dx) (x-x1).
So
the slope of the tangent dy/dx is gotten by differentiating y =
1+1/x.
dy/dx = (1+1/x)' =
-1/x^2.
Therefore at x1 dy/dx = -1/x1^2. At x1, y1 =
1+1/x1.
So the tangent (at x1,y1) is given
by:
y- (1+1/x1) = (-1/x2^2 (x-x1).....(1) Since this line
passes through (3,0) , it should satisfy eq (1).
0-1-1/x1 =
(-1/x1^2) (3-x1)
(-1-1/x1)(-x1^2) =
3-x1.
x1^2+x1+x1-3 = 0.
x^2
+2x-3 = 0.
(x1+3)(x1-1).
So
x1 = -3 , or x1 = 1.
Therefore y1 = 1+1/x1 . Or y1 =
1-1/3 = 2/3 when x= -3
y1 = 1+1/1 = 2 , when x1 =
1.
Therefore the tangents at (-3,2/3) and (1, 2) on the
curve y = 1+1/x passes the point (3,0).
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