Math Problem Statement

Find the exact value of each expression, if it is defined. (If an answer is undefined, enter UNDEFINED.) (a) sin−1(−1) (b) sin−1  2 2 (c) sin−1(−5)

Solution

To solve these, let's recall that the function sin1(x)\sin^{-1}(x), or the inverse sine function (arcsin), is defined only for values xx in the range [1,1][-1, 1]. The output (or range) of sin1(x)\sin^{-1}(x) is restricted to [π2,π2][- \frac{\pi}{2}, \frac{\pi}{2}].

Solution

(a) sin1(1)\sin^{-1}(-1)

Since 1-1 is within the range [1,1][-1, 1], we can evaluate it: sin1(1)=π2\sin^{-1}(-1) = -\frac{\pi}{2} This is because sin(π2)=1\sin\left(-\frac{\pi}{2}\right) = -1.

Answer: π2-\frac{\pi}{2}


(b) sin1(22)\sin^{-1}\left(\frac{\sqrt{2}}{2}\right)

Since 22\frac{\sqrt{2}}{2} is within the range [1,1][-1, 1], we can evaluate it: sin1(22)=π4\sin^{-1}\left(\frac{\sqrt{2}}{2}\right) = \frac{\pi}{4} This is because sin(π4)=22\sin\left(\frac{\pi}{4}\right) = \frac{\sqrt{2}}{2}.

Answer: π4\frac{\pi}{4}


(c) sin1(5)\sin^{-1}(-5)

Since 5-5 is outside the range [1,1][-1, 1], sin1(5)\sin^{-1}(-5) is undefined.

Answer: UNDEFINED


Would you like a more detailed explanation for any of these solutions?


Related Questions

  1. What is the exact value of sin1(1)\sin^{-1}(1)?
  2. How would you evaluate cos1(1)\cos^{-1}(-1)?
  3. Why is the domain of sin1(x)\sin^{-1}(x) limited to [1,1][-1, 1]?
  4. How do you evaluate sin(sin1(x))\sin\left(\sin^{-1}(x)\right) for xx within [1,1][-1, 1]?
  5. What is the value of tan1(1)\tan^{-1}(1) in terms of π\pi?

Tip

When working with inverse trigonometric functions, always check if the input lies within the domain, as values outside of the defined range will be undefined.

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Math Problem Analysis

Mathematical Concepts

Inverse Trigonometric Functions
Domain and Range
Trigonometry

Formulas

sin^{-1}(x), or arcsin, where sin^{-1}(x) is defined only for x in the range [-1, 1]
Range of sin^{-1}(x) is [-π/2, π/2]

Theorems

The domain restriction for inverse sine functions

Suitable Grade Level

Grades 10-12