Math Problem Statement

Find the derivative of the function g(x) = √(1 - x) using the definition of derivative.

Solution

To find the derivative of the given function g(x)=1xg(x) = \sqrt{1 - x} using the definition of the derivative, we'll follow these steps.

Definition of Derivative:

The derivative of a function g(x)g(x) at a point xx is given by the limit: g(x)=limh0g(x+h)g(x)hg'(x) = \lim_{h \to 0} \frac{g(x+h) - g(x)}{h}

Step-by-Step Process:

  1. Substitute g(x+h)g(x+h): g(x+h)=1(x+h)=1xhg(x+h) = \sqrt{1 - (x+h)} = \sqrt{1 - x - h}

  2. Substitute into the definition of derivative: g(x)=limh01xh1xhg'(x) = \lim_{h \to 0} \frac{\sqrt{1 - x - h} - \sqrt{1 - x}}{h}

  3. Rationalize the numerator: To simplify this expression, we multiply the numerator and denominator by the conjugate of the numerator: 1xh1xh×1xh+1x1xh+1x\frac{\sqrt{1 - x - h} - \sqrt{1 - x}}{h} \times \frac{\sqrt{1 - x - h} + \sqrt{1 - x}}{\sqrt{1 - x - h} + \sqrt{1 - x}} This results in: (1xh)(1x)h(1xh+1x)\frac{(1 - x - h) - (1 - x)}{h \left(\sqrt{1 - x - h} + \sqrt{1 - x}\right)} Simplifying the numerator: hh(1xh+1x)\frac{-h}{h \left(\sqrt{1 - x - h} + \sqrt{1 - x}\right)} Cancel the hh terms: 11xh+1x\frac{-1}{\sqrt{1 - x - h} + \sqrt{1 - x}}

  4. Take the limit as h0h \to 0: As h0h \to 0, 1xh1x\sqrt{1 - x - h} \to \sqrt{1 - x}. Therefore, the limit becomes: g(x)=121xg'(x) = \frac{-1}{2\sqrt{1 - x}}

Final Answer:

g(x)=121xg'(x) = \frac{-1}{2\sqrt{1 - x}}

Would you like any additional details or have any questions about this solution?

Related Questions:

  1. How do you use the product rule to differentiate complex functions?
  2. What is the chain rule in calculus, and how does it apply to this problem?
  3. How can you find the derivative of implicit functions?
  4. What are some other methods to compute derivatives besides the definition of the derivative?
  5. How do higher-order derivatives work, and how would you compute them for this function?

Tip:

Always check if you can simplify expressions by multiplying by conjugates when dealing with square roots in derivatives!

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Calculus
Derivatives
Limits
Rationalization

Formulas

g'(x) = lim(h -> 0) [g(x + h) - g(x)] / h
Rationalization: (√a - √b) * (√a + √b) = a - b

Theorems

Definition of Derivative
Limit Theorem

Suitable Grade Level

Grades 11-12