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.