Math Problem Statement

Solve this

Solution

To find dydx\frac{dy}{dx} given that x=eyx = e^y, we can follow these steps:

  1. Express yy in terms of xx: Since x=eyx = e^y, we can take the natural logarithm of both sides: ln(x)=ln(ey)    ln(x)=y\ln(x) = \ln(e^y) \implies \ln(x) = y So, y=ln(x)y = \ln(x).

  2. Differentiate both sides with respect to xx: ddx(y)=ddx(ln(x))\frac{d}{dx}(y) = \frac{d}{dx}(\ln(x)) Using the chain rule on the left-hand side and the known derivative of ln(x)\ln(x) on the right-hand side, we get: dydx=1x\frac{dy}{dx} = \frac{1}{x}

So, dydx=1x\frac{dy}{dx} = \frac{1}{x}.

Let's check the options provided:

(a) 1yxx\frac{1 - \frac{y}{x}}{x}

(b) 1+yx1 + \frac{y}{x}

(c) xyxlogx\frac{x - y}{x \log x}

(d) x+yxlogx\frac{x + y}{x \log x}

None of these options match dydx=1x\frac{dy}{dx} = \frac{1}{x}. This suggests that there might be a typographical error in the problem statement or in the provided options, or it might require further simplification.

To double-check, we will solve this again using implicit differentiation on the original equation x=eyx = e^y:

  1. Differentiate both sides with respect to xx: ddx(x)=ddx(ey)\frac{d}{dx}(x) = \frac{d}{dx}(e^y) The derivative of xx with respect to xx is 1, and the derivative of eye^y with respect to xx using the chain rule is eydydxe^y \cdot \frac{dy}{dx}.

    So, we get: 1=eydydx1 = e^y \cdot \frac{dy}{dx}

  2. Solve for dydx\frac{dy}{dx}: dydx=1ey\frac{dy}{dx} = \frac{1}{e^y} Since x=eyx = e^y, we substitute eye^y with xx: dydx=1x\frac{dy}{dx} = \frac{1}{x}

So, dydx=1x\frac{dy}{dx} = \frac{1}{x} again.

The correct derivative should indeed be 1x\frac{1}{x}, which does not match any of the given options. Therefore, there might be an error in the provided choices. If this happens often, I would recommend double-checking with a teacher or an authoritative source.

Do you want more details or have any questions?

Here are five more questions for you to consider:

  1. How do you find the second derivative of a function implicitly defined?
  2. What is the method to solve differential equations of the form dydx=f(x,y)\frac{dy}{dx} = f(x, y)?
  3. How do you find the critical points of a function?
  4. What is the process for using L'Hôpital's rule for indeterminate forms?
  5. How do you compute the integral of 1x\frac{1}{x}?

Tip: When differentiating implicitly, remember to apply the chain rule carefully to account for dependent variables.

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Math Problem Analysis

Mathematical Concepts

Implicit Differentiation
Chain Rule
Natural Logarithm

Formulas

Chain Rule
Derivative of Natural Logarithm

Theorems

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Suitable Grade Level

Advanced High School