Math Problem Statement

Differentiate y = sin^(-1)(x/2).

Solution

The given problem asks for the differentiation of the function:
y=sin1(x2).y = \sin^{-1}\left(\frac{x}{2}\right).

Solution:

To differentiate this, we use the chain rule and the known derivative of the inverse sine function.

Step 1: Recall the derivative formula for sin1(u)\sin^{-1}(u):

ddx(sin1(u))=11u2dudx.\frac{d}{dx} \left(\sin^{-1}(u)\right) = \frac{1}{\sqrt{1 - u^2}} \cdot \frac{du}{dx}. Here, u=x2u = \frac{x}{2}.

Step 2: Apply the chain rule:

Now, differentiate the function step by step.

y=sin1(x2)dydx=11(x2)2ddx(x2).y = \sin^{-1}\left(\frac{x}{2}\right) \quad \Rightarrow \quad \frac{dy}{dx} = \frac{1}{\sqrt{1 - \left(\frac{x}{2}\right)^2}} \cdot \frac{d}{dx}\left(\frac{x}{2}\right).

Step 3: Simplify:

First, simplify the square inside the square root: (x2)2=x24.\left(\frac{x}{2}\right)^2 = \frac{x^2}{4}. Thus: dydx=11x2412.\frac{dy}{dx} = \frac{1}{\sqrt{1 - \frac{x^2}{4}}} \cdot \frac{1}{2}.

Step 4: Combine terms:

The denominator simplifies to: 1x24=4x24=4x22.\sqrt{1 - \frac{x^2}{4}} = \sqrt{\frac{4 - x^2}{4}} = \frac{\sqrt{4 - x^2}}{2}.

Thus: dydx=14x2212.\frac{dy}{dx} = \frac{1}{\frac{\sqrt{4 - x^2}}{2}} \cdot \frac{1}{2}.

Step 5: Final simplification:

dydx=24x212=14x2.\frac{dy}{dx} = \frac{2}{\sqrt{4 - x^2}} \cdot \frac{1}{2} = \frac{1}{\sqrt{4 - x^2}}.

Final Answer:

y=14x2.y' = \frac{1}{\sqrt{4 - x^2}}.

Would you like further explanation or another example?


Here are 5 related questions you could explore:

  1. What is the derivative of sin1(x)\sin^{-1}(x)?
  2. How do you differentiate cos1(u)\cos^{-1}(u) using the chain rule?
  3. What are the domain restrictions for the function sin1(x)\sin^{-1}(x)?
  4. How does the chain rule apply to more complicated inverse trigonometric functions?
  5. What is the integral of 14x2\frac{1}{\sqrt{4 - x^2}}?

Tip: Inverse trigonometric functions often require special care with domain and range when differentiating or integrating.

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Math Problem Analysis

Mathematical Concepts

Differentiation
Inverse Trigonometric Functions
Chain Rule

Formulas

d/dx(sin^(-1)(u)) = 1 / sqrt(1 - u^2) * du/dx
(d/dx)(sin^(-1)(x/2)) = 1 / sqrt(1 - (x/2)^2) * d/dx(x/2)

Theorems

Chain Rule

Suitable Grade Level

Grades 11-12