Math Problem Statement

Find the equation of the normal line to the curve y = 3tan(2x) + 1 at the point with x_0 = π/2.

Solution

To determine the equation of the normal line to the curve y=3tan(2x)+1y = 3 \tan(2x) + 1 at the point where x0=π2x_0 = \frac{\pi}{2}, we follow these steps:

  1. Find the point on the curve: Substitute x0=π2x_0 = \frac{\pi}{2} into the equation y=3tan(2x)+1y = 3 \tan(2x) + 1.

    y0=3tan(2π2)+1=3tan(π)+1=30+1=1y_0 = 3 \tan\left(2 \cdot \frac{\pi}{2}\right) + 1 = 3 \tan(\pi) + 1 = 3 \cdot 0 + 1 = 1

    Thus, the point on the curve is (π2,1)\left(\frac{\pi}{2}, 1\right).

  2. Find the derivative of the curve: The derivative yy' represents the slope of the tangent line. We need to differentiate y=3tan(2x)+1y = 3 \tan(2x) + 1.

    [ y' = \frac{d}{dx} [3 \tan(2x) + 1] = 3 \cdot \frac{d}{dx} [\tan(2x)] = 3 \cdot 2 \sec^2(2x) = 6 \sec^2(2x) ]

    Evaluate the derivative at x=π2x = \frac{\pi}{2}:

    yx=π2=6sec2(2π2)=6sec2(π)=61=6y' \bigg|_{x = \frac{\pi}{2}} = 6 \sec^2 \left(2 \cdot \frac{\pi}{2}\right) = 6 \sec^2 (\pi) = 6 \cdot 1 = 6

  3. Find the slope of the normal line: The slope of the normal line is the negative reciprocal of the slope of the tangent line.

    mnormal=1y=16m_{\text{normal}} = -\frac{1}{y'} = -\frac{1}{6}

  4. Form the equation of the normal line: Use the point-slope form yy1=m(xx1)y - y_1 = m(x - x_1) with (π2,1)\left(\frac{\pi}{2}, 1\right) and mnormal=16m_{\text{normal}} = -\frac{1}{6}.

    y1=16(xπ2)y - 1 = -\frac{1}{6} \left(x - \frac{\pi}{2}\right)

    Simplify to get the equation in standard form:

    y1=16x+π12y - 1 = -\frac{1}{6}x + \frac{\pi}{12} 6y6=x+π26y - 6 = -x + \frac{\pi}{2} x+6yπ26=0x + 6y - \frac{\pi}{2} - 6 = 0 x+6yπ26=0or equivalentlyx+6y6π2=0x + 6y - \frac{\pi}{2} - 6 = 0 \quad \text{or equivalently} \quad x + 6y - 6 - \frac{\pi}{2} = 0

Now, comparing this with the provided options, we need to clear the denominators and match the format. The correct option is:

2x+12y12π=02x + 12y - 12 - \pi = 0

So, the correct answer is: 2x+12y12π=0\boxed{2x + 12y - 12 - \pi = 0}

Would you like more details or have any questions about this solution?

Here are some related questions you might find helpful:

  1. How do you find the tangent line to a curve at a given point?
  2. What is the difference between the tangent and the normal lines to a curve?
  3. How do you differentiate trigonometric functions?
  4. Can you explain the geometric interpretation of the derivative?
  5. What are the applications of normal and tangent lines in real-world problems?

Tip: When finding the equation of a normal line, remember to always use the negative reciprocal of the tangent's slope.

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Math Problem Analysis

Mathematical Concepts

Differentiation
Trigonometric Functions
Tangents and Normals

Formulas

y' = 3 * 2 * sec^2(2x) for the derivative of y = 3tan(2x) + 1
Slope of the normal = -1 / (Slope of the tangent)
Point-slope form of a line: y - y1 = m(x - x1)

Theorems

Derivative rules for trigonometric functions
Point-slope form of linear equations

Suitable Grade Level

Grades 11-12