Math Problem Statement

Given each function, find the equation of the tangent line at each point: y=3(x+1)^2 at the point (2,27)

Solution

To find the equation of the tangent line to the function y=3(x+1)2y = 3(x + 1)^2 at the point (2,27)(2, 27), we follow these steps:

Step 1: Find the derivative of the function

The derivative of a function represents the slope of the tangent line at any point. To find the derivative of y=3(x+1)2y = 3(x + 1)^2, we apply the chain rule:

dydx=32(x+1)ddx(x+1)\frac{dy}{dx} = 3 \cdot 2(x + 1) \cdot \frac{d}{dx}(x + 1) Since ddx(x+1)=1\frac{d}{dx}(x + 1) = 1, the derivative simplifies to: dydx=6(x+1)\frac{dy}{dx} = 6(x + 1)

Step 2: Evaluate the derivative at x=2x = 2

The slope of the tangent line at x=2x = 2 is found by plugging x=2x = 2 into the derivative: dydxx=2=6(2+1)=6×3=18\frac{dy}{dx} \bigg|_{x = 2} = 6(2 + 1) = 6 \times 3 = 18

Thus, the slope of the tangent line at (2,27)(2, 27) is 18.

Step 3: Use the point-slope form of the tangent line

The point-slope form of a line is given by: yy1=m(xx1)y - y_1 = m(x - x_1) where mm is the slope and (x1,y1)(x_1, y_1) is the point of tangency. In this case, m=18m = 18 and (x1,y1)=(2,27)(x_1, y_1) = (2, 27).

Substituting these values into the point-slope form: y27=18(x2)y - 27 = 18(x - 2) Simplifying the equation: y27=18x36y - 27 = 18x - 36 y=18x36+27y = 18x - 36 + 27 y=18x9y = 18x - 9

Final Answer:

The equation of the tangent line is: y=18x9y = 18x - 9

Would you like further explanation or details on any of the steps?


Here are 5 related questions for further exploration:

  1. How do you find the equation of a tangent line for implicit functions?
  2. What is the geometric interpretation of a derivative at a point?
  3. How do you apply the chain rule to more complex functions?
  4. What is the difference between a secant line and a tangent line?
  5. How would the equation change if the function was cubic?

Tip: When finding the tangent line, always double-check if the point given lies on the curve by substituting it into the original function.

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Math Problem Analysis

Mathematical Concepts

Calculus
Derivatives
Tangent Line

Formulas

Derivative of a function: dy/dx
Point-slope form of a line: y - y1 = m(x - x1)

Theorems

Chain Rule

Suitable Grade Level

Grades 11-12 (or early college level)