Math Problem Statement

give me the derivative of this

Give me the derivative of this equation: xsin(x^3 + y) = 2x + sec(xy)

Solution

To find the derivative of the equation

xsin(x3+y)=2x+sec(xy)x \sin(x^3 + y) = 2x + \sec(xy)

with respect to xx, we'll use implicit differentiation since yy is likely a function of xx.

Step-by-Step Differentiation

  1. Differentiate the Left Side:

    • The left side is xsin(x3+y)x \sin(x^3 + y).
    • Use the product rule: ddx[uv]=uv+uv\frac{d}{dx}[u \cdot v] = u' \cdot v + u \cdot v', where u=xu = x and v=sin(x3+y)v = \sin(x^3 + y).

    Differentiating: ddx(xsin(x3+y))=1sin(x3+y)+xcos(x3+y)ddx(x3+y)\frac{d}{dx}\left(x \sin(x^3 + y)\right) = 1 \cdot \sin(x^3 + y) + x \cdot \cos(x^3 + y) \cdot \frac{d}{dx}(x^3 + y)

    Now, differentiate x3+yx^3 + y with respect to xx: ddx(x3+y)=3x2+dydx\frac{d}{dx}(x^3 + y) = 3x^2 + \frac{dy}{dx}

    Substitute this back: ddx(xsin(x3+y))=sin(x3+y)+xcos(x3+y)(3x2+dydx)\frac{d}{dx}\left(x \sin(x^3 + y)\right) = \sin(x^3 + y) + x \cos(x^3 + y) (3x^2 + \frac{dy}{dx})

  2. Differentiate the Right Side:

    • The right side is 2x+sec(xy)2x + \sec(xy).
    • Differentiate term by term:

    For 2x2x, we get 22.

    For sec(xy)\sec(xy), use the chain rule. The derivative of sec(u)\sec(u) is sec(u)tan(u)\sec(u) \tan(u), so: ddxsec(xy)=sec(xy)tan(xy)ddx(xy)\frac{d}{dx} \sec(xy) = \sec(xy) \tan(xy) \cdot \frac{d}{dx}(xy)

    Now, differentiate xyxy with respect to xx: ddx(xy)=y+xdydx\frac{d}{dx}(xy) = y + x \frac{dy}{dx}

    Substitute this back: ddxsec(xy)=sec(xy)tan(xy)(y+xdydx)\frac{d}{dx} \sec(xy) = \sec(xy) \tan(xy) (y + x \frac{dy}{dx})

    So the derivative of the right side is: 2+sec(xy)tan(xy)(y+xdydx)2 + \sec(xy) \tan(xy) (y + x \frac{dy}{dx})

  3. Combine and Solve for dydx\frac{dy}{dx}: We now have the following equation:

    sin(x3+y)+xcos(x3+y)(3x2+dydx)=2+sec(xy)tan(xy)(y+xdydx)\sin(x^3 + y) + x \cos(x^3 + y) (3x^2 + \frac{dy}{dx}) = 2 + \sec(xy) \tan(xy) (y + x \frac{dy}{dx})

    Now, isolate dydx\frac{dy}{dx} to solve for it. This requires moving terms with dydx\frac{dy}{dx} to one side and factoring it out.

Would you like me to continue with the detailed algebraic manipulation to solve for dydx\frac{dy}{dx}?


Related Questions

  1. What is implicit differentiation and how is it used?
  2. Can we apply the chain rule to any trigonometric function composition?
  3. How do we handle products of functions when differentiating implicitly?
  4. Are there alternative methods to solve implicit differentiation problems like this?
  5. How can we confirm the correctness of an implicit derivative?

Tip

When dealing with implicit differentiation, always apply the chain rule carefully to each term involving yy, treating yy as a function of xx.

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Math Problem Analysis

Mathematical Concepts

Implicit Differentiation
Trigonometric Functions
Chain Rule
Product Rule

Formulas

Product rule: (uv)' = u'v + uv'
Chain rule: (f(g(x)))' = f'(g(x)) * g'(x)
Derivative of sin(u): cos(u) * u'
Derivative of sec(u): sec(u) * tan(u) * u'

Theorems

Implicit Differentiation

Suitable Grade Level

Grades 11-12