Math Problem Statement

x³+sin(xy) =3 , dy/dx =

Solution

To find dydx\frac{dy}{dx} from the equation x3+sin(xy)=3x^3 + \sin(xy) = 3, we will use implicit differentiation.

Steps:

  1. Differentiate both sides of the equation with respect to xx:

ddx(x3+sin(xy))=ddx(3)\frac{d}{dx}(x^3 + \sin(xy)) = \frac{d}{dx}(3)

The right-hand side, being a constant (3), has a derivative of 0:

ddx(3)=0\frac{d}{dx}(3) = 0

Now, let's differentiate the left-hand side.

  1. Differentiate x3x^3:

ddx(x3)=3x2\frac{d}{dx}(x^3) = 3x^2

  1. Differentiate sin(xy)\sin(xy):

We need to use the chain rule and product rule here. Consider sin(xy)\sin(xy) as a composite function. First, differentiate the outer function (sin), then the inner function xyxy:

ddx(sin(xy))=cos(xy)ddx(xy)\frac{d}{dx}(\sin(xy)) = \cos(xy) \cdot \frac{d}{dx}(xy)

Now, apply the product rule to xyxy:

ddx(xy)=y+xdydx\frac{d}{dx}(xy) = y + x \frac{dy}{dx}

Thus, the derivative of sin(xy)\sin(xy) is:

cos(xy)(y+xdydx)\cos(xy) \cdot (y + x \frac{dy}{dx})

  1. Putting it all together:

Now, we have:

3x2+cos(xy)(y+xdydx)=03x^2 + \cos(xy)(y + x \frac{dy}{dx}) = 0

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

Isolate the term involving dydx\frac{dy}{dx}:

cos(xy)(y+xdydx)=3x2\cos(xy)(y + x \frac{dy}{dx}) = -3x^2

Now, expand the left-hand side:

cos(xy)y+cos(xy)xdydx=3x2\cos(xy) y + \cos(xy) x \frac{dy}{dx} = -3x^2

Next, isolate the term with dydx\frac{dy}{dx}:

cos(xy)xdydx=3x2cos(xy)y\cos(xy) x \frac{dy}{dx} = -3x^2 - \cos(xy) y

Finally, solve for dydx\frac{dy}{dx}:

dydx=3x2cos(xy)ycos(xy)x\frac{dy}{dx} = \frac{-3x^2 - \cos(xy) y}{\cos(xy) x}

Final answer:

dydx=3x2cos(xy)ycos(xy)x\frac{dy}{dx} = \frac{-3x^2 - \cos(xy) y}{\cos(xy) x}

Would you like further clarification or details?

Related Questions:

  1. What is implicit differentiation, and why do we use it in this case?
  2. How does the product rule apply when differentiating xyxy?
  3. Can we solve for yy explicitly from x3+sin(xy)=3x^3 + \sin(xy) = 3?
  4. How does the chain rule work when differentiating composite functions like sin(xy)\sin(xy)?
  5. What would change if the equation were x3+cos(xy)=3x^3 + \cos(xy) = 3?

Tip: Implicit differentiation is useful when dealing with equations where yy is a function of xx but is not easily isolated.

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Math Problem Analysis

Mathematical Concepts

Implicit Differentiation
Chain Rule
Product Rule
Trigonometric Derivatives

Formulas

Derivative of x^3 is 3x^2
Derivative of sin(xy) is cos(xy) * (y + x * dy/dx)

Theorems

Chain Rule
Product Rule

Suitable Grade Level

Grades 11-12 (Calculus)