Find the equation of the tangent line to the curve y = x2 – 2x +7 which is
(a) Parallel to the line 2x – y + 9 = 0
(b) Perpendicular to the line 5y – 15x = 13.
The equation of the given curve is. (-∞,-1)
On differentiating with respect to x, we get:
(3, ∞)
(a) The equation of the line is 2x − y + 9 = 0.
2x − y + 9 = 0 ⇒ y = 2x + 9
This is of the form y = mx + c.
∴ Slope of the line = 2
If a tangent is parallel to the line 2x − y + 9 = 0, then the slope of the tangent is equal to the slope of the line.
Therefore, we have:
2 = 2x – 2
(-∞, –1)
Now, x = 2
(3, ∞) y = 4 − 4 + 7 = 7
Thus, the equation of the tangent passing through (2, 7) is given by,


