The equation of the tangent line to the curve $y = x^2-2x+5$ which is parallel to the line $4x - y + 1 = 0$ is |
$4x-y-1=0$ $4x-y-4=0$ $x+4y-4=0$ $x+4y-1=0$ |
$4x-y-4=0$ |
The correct answer is Option (2) → $4x-y-4=0$ ** The line $4x - y + 1 = 0$ has slope: $y = 4x + 1 \;\Rightarrow\; m = 4$ For the tangent to be parallel, its slope must also be $4$. Curve: $y = x^2 - 2x + 5$ Derivative: $y' = 2x - 2$ Set slope equal to $4$: $2x - 2 = 4$ $2x = 6$ $x = 3$ Corresponding $y$: $y = 3^2 - 2\cdot3 + 5 = 9 - 6 + 5 = 8$ Equation of tangent at $(3,8)$ with slope $4$: $y - 8 = 4(x - 3)$ $y = 4x - 12 + 8$ $y = 4x - 4$ Answer: $y = 4x - 4$ |