Math Problem Statement

but today you're on board the spaceship #243570664, and the captain is asking to solve tricky "ZP" (Z Planet) problem (you know what it means when captain is "asking"... that's an order):

(!!! If your answer is a fractions report it in an exact format, like 8510785107 , 229137229137)

Now, let f(x)=x5xx^{5x}. Use logarithmic differentiation to determine the (ZP) derivative.

f'(x)=f′(x)=   

                  (Enter the answer in simplified form)

f'(1)=f′(1)=   

!!! The challenge is that some of the Z-Planet laws are different. In particular,  "power rule" on Earth, d/dx x^n = nxn1nx^{n-1} , on Z planet is "twisted" as the following:  

 ddxxn=n2xn1n^2x^{n-1}  (ddxconst=0ddxconst=0) , and

the derivative of log function, ddxln(x)=1xddxln(x)=1/x , turns into "ZP" oddness:  ddxln(x)=exe^{x} .

Solution

Let's tackle this tricky Z Planet problem by applying logarithmic differentiation, keeping in mind the modified "power rule" and logarithmic derivative rules from Z Planet.

We are given that:

f(x)=x5xf(x) = x^{5x}

Step 1: Logarithmic Differentiation

We start by taking the natural logarithm (on Z Planet!) of both sides of the equation to simplify the differentiation.

ln(f(x))=ln(x5x)\ln(f(x)) = \ln(x^{5x})

Using the properties of logarithms on Earth, ln(xa)=aln(x)\ln(x^a) = a\ln(x). But, since we're on Z Planet, we need to differentiate this expression using their unique laws.

Thus, we rewrite the equation:

ln(f(x))=5xln(x)\ln(f(x)) = 5x \cdot \ln(x)

Step 2: Differentiate both sides

Now, we differentiate both sides with respect to xx, applying the Z Planet derivative rules.

For the left-hand side, we have:

ddxln(f(x))=f(x)f(x)\frac{d}{dx} \ln(f(x)) = \frac{f'(x)}{f(x)}

For the right-hand side, we need to apply the product rule to differentiate 5xln(x)5x \cdot \ln(x).

ddx(5xln(x))=5(ddx(x)ln(x)+xddxln(x))\frac{d}{dx} \left( 5x \cdot \ln(x) \right) = 5 \left( \frac{d}{dx}(x) \ln(x) + x \frac{d}{dx} \ln(x) \right)

On Z Planet:

  • ddx(x)=1\frac{d}{dx}(x) = 1
  • ddxln(x)=ex\frac{d}{dx} \ln(x) = e^x (instead of 1x\frac{1}{x} as on Earth)

So, we get:

ddx(5xln(x))=5(1ln(x)+xex)\frac{d}{dx} \left( 5x \cdot \ln(x) \right) = 5 \left( 1 \cdot \ln(x) + x \cdot e^x \right)

=5(ln(x)+xex)= 5 \left( \ln(x) + x e^x \right)

Step 3: Solve for f(x)f'(x)

Now, equating both sides:

f(x)f(x)=5(ln(x)+xex)\frac{f'(x)}{f(x)} = 5 \left( \ln(x) + x e^x \right)

Multiply both sides by f(x)f(x) to isolate f(x)f'(x):

f(x)=f(x)5(ln(x)+xex)f'(x) = f(x) \cdot 5 \left( \ln(x) + x e^x \right)

Since f(x)=x5xf(x) = x^{5x}, we substitute:

f(x)=x5x5(ln(x)+xex)f'(x) = x^{5x} \cdot 5 \left( \ln(x) + x e^x \right)

This is the derivative f(x)f'(x) in simplified form!

Step 4: Evaluate f(1)f'(1)

To find f(1)f'(1), substitute x=1x = 1 into the derivative:

f(1)=151=1f(1) = 1^{5 \cdot 1} = 1

Now, plug x=1x = 1 into the derivative expression:

f(1)=15(ln(1)+1e1)f'(1) = 1 \cdot 5 \left( \ln(1) + 1 \cdot e^1 \right)

Since ln(1)=0\ln(1) = 0 and e1=ee^1 = e, we get:

f(1)=5(0+e)=5ef'(1) = 5 \cdot (0 + e) = 5e

Thus:

f(1)=5ef'(1) = 5e

Final Answers:

f(x)=x5x5(ln(x)+xex)f'(x) = x^{5x} \cdot 5 \left( \ln(x) + x e^x \right) f(1)=5ef'(1) = 5e

Would you like more details or further clarification?


Related Questions:

  1. How would the derivative change if the power of xx was 3x3x instead of 5x5x?
  2. Can you explain how the Earth’s power rule would apply to x5xx^{5x}?
  3. How would the product rule on Z Planet differ from Earth's version?
  4. What would be the integral of exe^x on Z Planet?
  5. If the function were x4xx^{4x}, how would the derivative change?

Tip: When using logarithmic differentiation, always remember that the product and chain rules must adapt to local (or Z-Planet) rules for correct application.

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Math Problem Analysis

Mathematical Concepts

Logarithmic Differentiation
Product Rule
Z Planet Derivative Rules
Exponential Functions

Formulas

f(x) = x^{5x}
ZP Power Rule: d/dx x^n = n^2 x^{n-1}
ZP Log Derivative: d/dx ln(x) = e^x
f'(x) = x^{5x} * 5 * (ln(x) + x e^x)
f'(1) = 5e

Theorems

Logarithmic Differentiation Theorem
Product Rule

Suitable Grade Level

Grades 11-12