Math Problem Statement

given the function y=2secx find the equation of the tangent at x = pi/6

Solution

To find the equation of the tangent to the function y=2sec(x)y = 2\sec(x) at x=π6x = \frac{\pi}{6}, follow these steps:

1. Differentiate the function:

The equation of the tangent line at a given point is found using the derivative of the function, which gives the slope of the tangent line.

We have y=2sec(x)y = 2\sec(x).

The derivative of sec(x)\sec(x) with respect to xx is:

ddx[sec(x)]=sec(x)tan(x)\frac{d}{dx}[\sec(x)] = \sec(x)\tan(x)

So, differentiating y=2sec(x)y = 2\sec(x) with respect to xx:

dydx=2sec(x)tan(x)\frac{dy}{dx} = 2\sec(x)\tan(x)

This gives the slope of the tangent line at any point xx.

2. Find the slope at x=π6x = \frac{\pi}{6}:

Now, substitute x=π6x = \frac{\pi}{6} into the derivative to find the slope of the tangent line.

At x=π6x = \frac{\pi}{6}: sec(π6)=1cos(π6)=132=23\sec\left(\frac{\pi}{6}\right) = \frac{1}{\cos\left(\frac{\pi}{6}\right)} = \frac{1}{\frac{\sqrt{3}}{2}} = \frac{2}{\sqrt{3}} tan(π6)=13\tan\left(\frac{\pi}{6}\right) = \frac{1}{\sqrt{3}}

Thus, the slope at x=π6x = \frac{\pi}{6} is:

dydxx=π6=22313=43\frac{dy}{dx}\bigg|_{x = \frac{\pi}{6}} = 2 \cdot \frac{2}{\sqrt{3}} \cdot \frac{1}{\sqrt{3}} = \frac{4}{3}

3. Find the point of tangency:

At x=π6x = \frac{\pi}{6}, substitute into the original function to find the corresponding yy-value.

y=2sec(π6)=223=43=433y = 2\sec\left(\frac{\pi}{6}\right) = 2 \cdot \frac{2}{\sqrt{3}} = \frac{4}{\sqrt{3}} = \frac{4\sqrt{3}}{3}

So, the point of tangency is (π6,433)\left(\frac{\pi}{6}, \frac{4\sqrt{3}}{3}\right).

4. Write the equation of the tangent line:

The equation 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.

Substituting the values m=43m = \frac{4}{3}, x1=π6x_1 = \frac{\pi}{6}, and y1=433y_1 = \frac{4\sqrt{3}}{3}:

y433=43(xπ6)y - \frac{4\sqrt{3}}{3} = \frac{4}{3}\left(x - \frac{\pi}{6}\right)

This is the equation of the tangent line.

Final Answer:

The equation of the tangent line to y=2sec(x)y = 2\sec(x) at x=π6x = \frac{\pi}{6} is:

y433=43(xπ6)y - \frac{4\sqrt{3}}{3} = \frac{4}{3}\left(x - \frac{\pi}{6}\right)

Let me know if you would like further details or have any questions.

Here are some related questions to deepen your understanding:

  1. How do you find the equation of the tangent line for a general function at a specific point?
  2. What is the difference between secant and tangent functions in terms of calculus and geometry?
  3. Can you find the normal line at the same point x=π6x = \frac{\pi}{6}?
  4. What is the significance of the derivative in determining the slope of a tangent?
  5. How would the equation change if the function were y=3sec(x)y = 3\sec(x)?

Tip: Always check whether the function has vertical asymptotes near the point of tangency to ensure the tangent exists.

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Math Problem Analysis

Mathematical Concepts

Trigonometry
Differentiation
Calculus
Tangent Line

Formulas

Derivative of sec(x): d/dx[sec(x)] = sec(x)tan(x)
Equation of a tangent line: y - y1 = m(x - x1)

Theorems

Differentiation rules
Trigonometric identities (sec and tan)

Suitable Grade Level

Grades 11-12 (Pre-Calculus/Calculus)