Math Problem Statement

find derivative of sec(y)=x^3 using implicit differentiation

Solution

To find the derivative of the equation sec(y)=x3\sec(y) = x^3 using implicit differentiation, follow these steps:

  1. Differentiate both sides of the equation with respect to xx, remembering that yy is a function of xx (so apply the chain rule when differentiating yy).

[ \frac{d}{dx}[\sec(y)] = \frac{d}{dx}[x^3] ]

  1. The derivative of sec(y)\sec(y) with respect to xx involves the chain rule. The derivative of sec(y)\sec(y) with respect to yy is sec(y)tan(y)\sec(y)\tan(y), but since yy is a function of xx, we must multiply by dydx\frac{dy}{dx} (the derivative of yy with respect to xx).

ddx[sec(y)]=sec(y)tan(y)dydx\frac{d}{dx}[\sec(y)] = \sec(y) \tan(y) \cdot \frac{dy}{dx}

  1. The derivative of x3x^3 is straightforward:

ddx[x3]=3x2\frac{d}{dx}[x^3] = 3x^2

  1. Now, combine both sides:

sec(y)tan(y)dydx=3x2\sec(y) \tan(y) \cdot \frac{dy}{dx} = 3x^2

  1. To isolate dydx\frac{dy}{dx}, divide both sides by sec(y)tan(y)\sec(y) \tan(y):

dydx=3x2sec(y)tan(y)\frac{dy}{dx} = \frac{3x^2}{\sec(y) \tan(y)}

  1. You could also simplify sec(y)tan(y)\sec(y) \tan(y) in terms of trigonometric functions, but this is the implicit derivative of yy with respect to xx.

Would you like to see further simplifications or explanations?

Here are 5 related questions to explore:

  1. What is implicit differentiation, and how does it differ from regular differentiation?
  2. How would you find the second derivative of the same equation?
  3. How do we simplify trigonometric derivatives involving secant and tangent?
  4. What is the significance of applying the chain rule in implicit differentiation?
  5. How can we check if a given function requires implicit differentiation?

Tip: Implicit differentiation is useful whenever you have an equation where yy is a function of xx but is not isolated.

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Math Problem Analysis

Mathematical Concepts

Implicit Differentiation
Trigonometric Derivatives
Chain Rule

Formulas

d/dx[sec(y)] = sec(y) * tan(y) * dy/dx
d/dx[x^3] = 3x^2

Theorems

Chain Rule
Implicit Differentiation

Suitable Grade Level

Grades 11-12 (Advanced High School Calculus)