Question
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
(ii) perpendicular to the line 5y – 15y = 13
Solution
The equation of curve is y = x2 – 2x + 7 ...(1)
(i) consider the line 
...(2)
Its slope 
Since tangent to the curve is parallel to line (2)
(ii) Consider the line 
...(3)
Its slope 
Since target to the curve is perpendicular to line (3)
