Math Problem Statement

If sin(xy) = x, then what is dy/dx?

Solution

We are given the equation:

sin(xy)=x\sin(xy) = x

We are asked to find dydx\frac{dy}{dx}. Let's differentiate both sides of this equation implicitly with respect to xx.

  1. Differentiate sin(xy)\sin(xy) using the chain rule: [ \frac{d}{dx}[\sin(xy)] = \cos(xy) \cdot \frac{d}{dx}[xy] ] Since xyxy is a product of two functions xx and yy, we apply the product rule: ddx[xy]=y+xdydx\frac{d}{dx}[xy] = y + x\frac{dy}{dx} So: ddx[sin(xy)]=cos(xy)(y+xdydx)\frac{d}{dx}[\sin(xy)] = \cos(xy) \cdot (y + x\frac{dy}{dx})

  2. Differentiate the right-hand side xx: ddx[x]=1\frac{d}{dx}[x] = 1

Now we have the equation: cos(xy)(y+xdydx)=1\cos(xy) \cdot (y + x\frac{dy}{dx}) = 1

  1. Solve for dydx\frac{dy}{dx}:

First, expand the left-hand side: cos(xy)y+cos(xy)xdydx=1\cos(xy) \cdot y + \cos(xy) \cdot x \frac{dy}{dx} = 1

Move the term cos(xy)y\cos(xy) \cdot y to the right side: cos(xy)xdydx=1cos(xy)y\cos(xy) \cdot x \frac{dy}{dx} = 1 - \cos(xy) \cdot y

Now, solve for dydx\frac{dy}{dx}: dydx=1cos(xy)yxcos(xy)\frac{dy}{dx} = \frac{1 - \cos(xy) \cdot y}{x \cos(xy)}

This matches option (D) in the given choices.

Thus, the correct answer is (D).


Would you like further details on any step?

Here are 5 questions related to this:

  1. How do you differentiate trigonometric functions implicitly?
  2. What is the chain rule and when is it applied in differentiation?
  3. How does the product rule work in calculus?
  4. Can you explain implicit differentiation in greater depth?
  5. How does solving for dydx\frac{dy}{dx} differ when dealing with implicit versus explicit functions?

Tip: When differentiating products of functions, always remember to apply the product rule carefully!

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Math Problem Analysis

Mathematical Concepts

Implicit Differentiation
Trigonometry
Calculus

Formulas

Chain Rule: d/dx[f(g(x))] = f'(g(x)) * g'(x)
Product Rule: d/dx[uv] = u'v + uv'

Theorems

Implicit Differentiation

Suitable Grade Level

Grades 11-12 (Advanced Calculus)