Find the equation of all lines having slope –1 that are tangents to the curve

It is given that equation of the curve y =

Now, slope of the tangent to the given curve at a point (x, y) is:



Now, if the slope of the tangent is -1, then we get,



(x-1)2 = 1


(x-1) = 1


x = 2, 0


So, when x = 2 then y = 1


And when x = 0 then y = 1


Therefore, required points are (0, -1) and (2, 1).


Now, the equation of the tangent (0,1) is given by:


y – (-1) = -1(x-0)


y + 1 = -x


y + x+ 1 = 0


And the equation of the tangent (2,1) is given by:


y – 1 = -1(x-2)


y - 1 = -x +2


y + x - 3 = 0


Therefore, the equations of the required lines are y + x+ 1 = 0 and y + x - 3 = 0.


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