Math Problem Statement

Find the derivative of the function y = (sqrt(x))^x.

Solution

We are tasked with finding dydx\frac{dy}{dx} for the given function y=(x)xy = (\sqrt{x})^x. Let's solve it step-by-step:

Step 1: Rewrite the function

Recall that x=x1/2\sqrt{x} = x^{1/2}. So, we rewrite: y=(x)x=(x1/2)x=xx/2.y = (\sqrt{x})^x = (x^{1/2})^x = x^{x/2}.

Step 2: Take the natural logarithm (logarithmic differentiation)

Taking the natural logarithm of both sides: lny=ln(xx/2).\ln y = \ln(x^{x/2}). Using the logarithm rule ln(ab)=blna\ln(a^b) = b \ln a: lny=x2lnx.\ln y = \frac{x}{2} \ln x.

Step 3: Differentiate both sides with respect to xx

Differentiate implicitly: 1ydydx=ddx(x2lnx).\frac{1}{y} \frac{dy}{dx} = \frac{d}{dx}\left(\frac{x}{2} \ln x\right).

Use the product rule for x2lnx\frac{x}{2} \ln x: ddx(x2lnx)=12lnx+x21x.\frac{d}{dx}\left(\frac{x}{2} \ln x\right) = \frac{1}{2} \ln x + \frac{x}{2} \cdot \frac{1}{x}. Simplify: ddx(x2lnx)=12lnx+12.\frac{d}{dx}\left(\frac{x}{2} \ln x\right) = \frac{1}{2} \ln x + \frac{1}{2}.

Thus: 1ydydx=12lnx+12.\frac{1}{y} \frac{dy}{dx} = \frac{1}{2} \ln x + \frac{1}{2}.

Step 4: Solve for dydx\frac{dy}{dx}

Multiply through by y=xx/2y = x^{x/2}: dydx=y(12lnx+12).\frac{dy}{dx} = y \left(\frac{1}{2} \ln x + \frac{1}{2}\right). Substitute y=xx/2y = x^{x/2} back: dydx=xx/2(12lnx+12).\frac{dy}{dx} = x^{x/2} \left(\frac{1}{2} \ln x + \frac{1}{2}\right).

Final Answer:

dydx=xx/2(12lnx+12).\frac{dy}{dx} = x^{x/2} \left(\frac{1}{2} \ln x + \frac{1}{2}\right).

Let me know if you need further explanation! Here are some related questions:

  1. What happens to the derivative if x=1x = 1?
  2. How can you simplify the expression further for large values of xx?
  3. Can we apply this process to other forms of y=(xa)xy = (x^a)^x?
  4. How does logarithmic differentiation help with more complex functions?
  5. Can this be solved using an alternative method, such as differentiating without logarithms?

Tip: For functions with variables in both the base and the exponent, logarithmic differentiation is often the simplest and most effective approach.

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Math Problem Analysis

Mathematical Concepts

Differentiation
Logarithmic Differentiation
Exponential Functions
Chain Rule
Product Rule

Formulas

y = (sqrt(x))^x = x^(x/2)
ln(a^b) = b * ln(a)
Product Rule: d/dx [u(x)v(x)] = u'(x)v(x) + u(x)v'(x)

Theorems

Logarithmic Differentiation

Suitable Grade Level

Grades 11-12