Math Problem Statement

simplify cos(arcsin(x))

Solution

To simplify cos(arcsin(x))\cos(\arcsin(x)), we proceed as follows:

  1. Let θ=arcsin(x)\theta = \arcsin(x). This means sin(θ)=x\sin(\theta) = x, and θ\theta is in the range [π2,π2][-\frac{\pi}{2}, \frac{\pi}{2}].
  2. From the Pythagorean identity, sin2(θ)+cos2(θ)=1\sin^2(\theta) + \cos^2(\theta) = 1, we find cos2(θ)=1sin2(θ)\cos^2(\theta) = 1 - \sin^2(\theta).
  3. Substitute sin(θ)=x\sin(\theta) = x:
    cos2(θ)=1x2\cos^2(\theta) = 1 - x^2
  4. Taking the square root, cos(θ)=1x2\cos(\theta) = \sqrt{1 - x^2}, since cos(θ)0\cos(\theta) \geq 0 in the range [π2,π2][-\frac{\pi}{2}, \frac{\pi}{2}].

Thus,
cos(arcsin(x))=1x2\cos(\arcsin(x)) = \sqrt{1 - x^2}


Do you want more details or have any questions?

Here are some related questions for further exploration:

  1. What is sin(arccos(x))\sin(\arccos(x))?
  2. How does the Pythagorean identity work with trigonometric functions?
  3. Can xx exceed the range [1,1][-1, 1] for arcsin(x)\arcsin(x)?
  4. How do we simplify tan(arcsin(x))\tan(\arcsin(x))?
  5. What happens when x=1x = 1 or x=1x = -1 in this expression?

Tip: Always remember that arcsin(x)\arcsin(x) and arccos(x)\arccos(x) involve principal branches, which restrict their output ranges to ensure they are functions.

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Math Problem Analysis

Mathematical Concepts

Trigonometry
Inverse Trigonometric Functions
Pythagorean Identity

Formulas

sin^2(θ) + cos^2(θ) = 1
cos(arcsin(x)) = sqrt(1 - x^2)

Theorems

Pythagorean Identity

Suitable Grade Level

Grades 10-12