Normal to the curve \( y=x^{3}-3 x+2 \) at the point \( (2,4) \) is
Step-by-step Solution:
To find the equation of the normal to the curve \( y = x^3 - 3x + 2 \) at the point \( (2,4) \)
Step 1: Compute the Derivative
The derivative of the given function represents the slope of the tangent line:
\[
\frac{dy}{dx} = \frac{d}{dx} (x^3 - 3x + 2)
\]
\[
\frac{dy}{dx} = 3x^2 - 3
\]
Step 2: Find the Slope at \( (2,4) \)
Substituting \( x = 2 \):
\[
\frac{dy}{dx} \bigg|_{x=2} = 3(2)^2 - 3 = 3(4) - 3 = 12 - 3 = 9
\]
Thus, the slope of the tangent at \( (2,4) \) is 9.
Step 3: Compute the Slope of the Normal
The slope of the normal line is the negative reciprocal of the tangent's slope:
\[
m_{\text{normal}} = -\frac{1}{9}
\]
Step 4: Equation of the Normal Line
Using the point-slope form of the equation of a line:
\[
y - y_1 = m (x - x_1)
\]
Substituting \( (x_1, y_1) = (2,4) \) and \( m = -\frac{1}{9} \):
\[
y - 4 = -\frac{1}{9} (x - 2)
\]
Multiplying both sides by 9 to eliminate fractions:
\[
9(y - 4) = -(x - 2)
\]
\[
9y - 36 = -x + 2
\]
\[
x + 9y = 38
\]
Final Answer:
\(
\mathbf{x + 9y = 38}
\)