Discussion Forum

A straight line parallel to the line 2x - y+ 5 : 0 is also a tangent to the curve y² = 4x+ 5. Then the point of contact is

Answer:

Explanation:

Given curve  is y² = 4x+5 on differentiating, we get

2y $\frac{dy}{dx}$ = 4

$\frac{dy}{dx} = \frac{2}{y}$

Given line is 2x - y + 5 = 0

Y = 2x + 5

slope of line is 2. Therefore,

2/y = 2 and y = 1

put y = 1 in the equation of curve, we get

1 = 4x +5

x = -1

Hence, point of contact is (- 1, 1)