Math Problem Statement

(x+h)-(x) over h f = squareroot of x

Solution

You seem to be asking for the expression f(x+h)f(x)h\frac{f(x+h) - f(x)}{h} where f(x)=xf(x) = \sqrt{x}. This expression represents the difference quotient, which is used to calculate the derivative of a function.

Let's simplify the difference quotient step by step:

Given f(x)=xf(x) = \sqrt{x}, the difference quotient is:

f(x+h)f(x)h=x+hxh\frac{f(x+h) - f(x)}{h} = \frac{\sqrt{x+h} - \sqrt{x}}{h}

To simplify this expression, we can multiply the numerator and the denominator by the conjugate of the numerator to eliminate the square roots. The conjugate of x+hx\sqrt{x+h} - \sqrt{x} is x+h+x\sqrt{x+h} + \sqrt{x}. So we multiply:

x+hxh×x+h+xx+h+x=(x+hx)(x+h+x)h(x+h+x)\frac{\sqrt{x+h} - \sqrt{x}}{h} \times \frac{\sqrt{x+h} + \sqrt{x}}{\sqrt{x+h} + \sqrt{x}} = \frac{(\sqrt{x+h} - \sqrt{x})(\sqrt{x+h} + \sqrt{x})}{h(\sqrt{x+h} + \sqrt{x})}

Using the difference of squares, the numerator simplifies as follows:

(x+h)2(x)2=(x+h)x=h(\sqrt{x+h})^2 - (\sqrt{x})^2 = (x+h) - x = h

So, the expression becomes:

hh(x+h+x)\frac{h}{h(\sqrt{x+h} + \sqrt{x})}

The hh in the numerator and denominator cancels out:

1x+h+x\frac{1}{\sqrt{x+h} + \sqrt{x}}

So the simplified difference quotient is:

1x+h+x\frac{1}{\sqrt{x+h} + \sqrt{x}}

This expression approaches the derivative of x\sqrt{x} as hh approaches 0.

Do you have any questions or need further clarification? Here are some related questions you might explore:

  1. What is the derivative of f(x)=xf(x) = \sqrt{x}?
  2. How would you find the derivative using the definition of a derivative?
  3. What happens if you set h=0h = 0 in the simplified expression?
  4. How do you find the derivative of x\sqrt{x} using the power rule?
  5. Can you find the second derivative of x\sqrt{x}?

Tip: Multiplying by the conjugate is a common technique used to simplify expressions involving square roots.

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Math Problem Analysis

Mathematical Concepts

Limits
Derivatives
Square Roots

Formulas

Difference quotient

Theorems

Definition of derivative

Suitable Grade Level

Advanced High School