Math Problem Statement

x=sec y ,\differentialDy\differentialDx=x=\text{sec y },\frac{\differentialD y}{\differentialD x}=

Solution

Given the equation x=sec(y)x = \sec(y), we want to find dydx\frac{dy}{dx}.

Step-by-step solution:

  1. Differentiate both sides of the equation x=sec(y)x = \sec(y) with respect to xx: ddx(x)=ddx(sec(y))\frac{d}{dx} \left( x \right) = \frac{d}{dx} \left( \sec(y) \right)

  2. The derivative of xx with respect to xx is simply 1: 1=ddx(sec(y))1 = \frac{d}{dx} \left( \sec(y) \right)

  3. Use the chain rule to differentiate sec(y)\sec(y) with respect to xx: ddx(sec(y))=sec(y)tan(y)dydx\frac{d}{dx} \left( \sec(y) \right) = \sec(y) \tan(y) \cdot \frac{dy}{dx}

  4. Now, set the derivatives equal to each other: 1=sec(y)tan(y)dydx1 = \sec(y) \tan(y) \cdot \frac{dy}{dx}

  5. Solve for dydx\frac{dy}{dx}: dydx=1sec(y)tan(y)\frac{dy}{dx} = \frac{1}{\sec(y) \tan(y)}

Since sec(y)=x\sec(y) = x, we substitute sec(y)\sec(y) and tan(y)\tan(y) in terms of xx:

  1. Using the identity tan2(y)=sec2(y)1\tan^2(y) = \sec^2(y) - 1, we know that: tan(y)=x21\tan(y) = \sqrt{x^2 - 1}

  2. Now substitute these into the expression for dydx\frac{dy}{dx}: dydx=1xx21\frac{dy}{dx} = \frac{1}{x \cdot \sqrt{x^2 - 1}}

Thus, the derivative is: dydx=1xx21\frac{dy}{dx} = \frac{1}{x \sqrt{x^2 - 1}}

Would you like more details on the steps or any clarifications?

Here are 5 related questions to expand on this concept:

  1. How would you differentiate y=cos1(x)y = \cos^{-1}(x) with respect to xx?
  2. What is the derivative of y=sec1(x)y = \sec^{-1}(x)?
  3. How can you apply the chain rule to a function like z=tan(sec(y))z = \tan(\sec(y))?
  4. What is the second derivative of y=sec1(x)y = \sec^{-1}(x)?
  5. How does the identity sec2(y)=1+tan2(y)\sec^2(y) = 1 + \tan^2(y) help in simplifying derivatives?

Tip: Always consider trigonometric identities when simplifying derivatives involving trigonometric functions!

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Math Problem Analysis

Mathematical Concepts

Trigonometry
Differentiation
Chain Rule
Trigonometric Identities

Formulas

x = sec(y)
dy/dx = 1 / (x sqrt(x^2 - 1))
sec^2(y) = 1 + tan^2(y)
tan(y) = sqrt(sec^2(y) - 1)

Theorems

Chain Rule
Trigonometric Derivatives
Pythagorean Trigonometric Identity

Suitable Grade Level

Grades 11-12 or early college calculus