Math Problem Statement

Find an equation of the tangent line to the curve y = tan^2(x) at the point (π/3, 3).

Solution

The problem asks for the equation of the tangent line to the curve y=tan2(x)y = \tan^2(x) at the point (π3,3)\left(\frac{\pi}{3}, 3 \right).

We need to:

  1. Differentiate y=tan2(x)y = \tan^2(x) to find the slope of the tangent line at x=π3x = \frac{\pi}{3}.
  2. Use the point-slope form of a line to write the equation.

Step 1: Find the derivative of y=tan2(x)y = \tan^2(x)

Using the chain rule: dydx=2tan(x)sec2(x)\frac{dy}{dx} = 2 \tan(x) \cdot \sec^2(x) This is the derivative of y=tan2(x)y = \tan^2(x).

Step 2: Evaluate the derivative at x=π3x = \frac{\pi}{3}

First, calculate tan(π3)\tan\left(\frac{\pi}{3}\right) and sec(π3)\sec\left(\frac{\pi}{3}\right): tan(π3)=3,sec(π3)=2\tan\left(\frac{\pi}{3}\right) = \sqrt{3}, \quad \sec\left(\frac{\pi}{3}\right) = 2 Now substitute into the derivative formula: dydxx=π3=23(22)=234=83\frac{dy}{dx} \Big|_{x = \frac{\pi}{3}} = 2 \cdot \sqrt{3} \cdot (2^2) = 2 \cdot \sqrt{3} \cdot 4 = 8\sqrt{3} So, the slope m=83m = 8\sqrt{3}.

Step 3: Find the equation of the tangent line

We use the point-slope form of a line: yy1=m(xx1)y - y_1 = m(x - x_1) where m=83m = 8\sqrt{3}, x1=π3x_1 = \frac{\pi}{3}, and y1=3y_1 = 3. Substituting these values: y3=83(xπ3)y - 3 = 8\sqrt{3} \left( x - \frac{\pi}{3} \right) Simplifying this into slope-intercept form y=mx+by = mx + b, we get: y=83x83π3+3y = 8\sqrt{3}x - 8\sqrt{3}\frac{\pi}{3} + 3 y=83x8π33+3y = 8\sqrt{3}x - \frac{8\pi\sqrt{3}}{3} + 3 So, m=83m = 8\sqrt{3} and b=38π33b = 3 - \frac{8\pi\sqrt{3}}{3}.

Let me know if you'd like further clarifications or additional steps.


Relative questions:

  1. How does the chain rule apply in differentiating tan2(x)\tan^2(x)?
  2. What is the point-slope form of a line, and why do we use it for tangent lines?
  3. Why is the derivative of tan(x)\tan(x) related to sec2(x)\sec^2(x)?
  4. How can we simplify terms involving π\pi in the final answer for bb?
  5. What would happen if we changed the function to cot(x)\cot(x) instead of tan(x)\tan(x)?

Tip: When solving problems involving the tangent line, always start by differentiating to find the slope before applying the point-slope formula.

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Math Problem Analysis

Mathematical Concepts

Differentiation
Trigonometric functions
Tangent line

Formulas

Derivative of y = tan^2(x)
Point-slope form: y - y1 = m(x - x1)

Theorems

Chain rule
Trigonometric identities (tan and sec)

Suitable Grade Level

Grades 11-12 (Calculus)