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Ch. 1 - Angles and the Trigonometric Functions
1์žฅ, ๋ฌธ์ œ 101

Find two values of ฮธ, 0 โ‰ค ฮธ < 2๐œ‹, that satisfy each equation. sin ฮธ = - โˆš2/2

๊ฒ€์ฆ๋œ ๋‹จ๊ณ„๋ณ„ ์•ˆ๋‚ด
1
Recognize that the equation is \( \sin \theta = -\frac{\sqrt{2}}{2} \). This means we are looking for angles \( \theta \) where the sine value is negative and equal to \( -\frac{\sqrt{2}}{2} \).
Recall the reference angle where \( \sin \theta = \frac{\sqrt{2}}{2} \) is \( \frac{\pi}{4} \). Since sine is negative, \( \theta \) must be in the third or fourth quadrants where sine values are negative.
Use the unit circle to find the two angles in the interval \( 0 \leq \theta < 2\pi \) that correspond to the sine value \( -\frac{\sqrt{2}}{2} \). These angles are \( \pi + \frac{\pi}{4} \) and \( 2\pi - \frac{\pi}{4} \).
Write the two solutions explicitly as \( \theta = \pi + \frac{\pi}{4} \) and \( \theta = 2\pi - \frac{\pi}{4} \).
Verify that both values lie within the given interval \( 0 \leq \theta < 2\pi \) and satisfy the original equation.

๋น„์Šทํ•œ ๋ฌธ์ œ์— ๋Œ€ํ•œ ๊ฒ€์ฆ๋œ ์˜์ƒ ๋‹ต๋ณ€:

์ด ์˜์ƒ ํ•ด๋ฒ•์€ ์œ„ ๋ฌธ์ œ์— ๋„์›€์ด ๋œ๋‹ค๊ณ  ํŠœํ„ฐ๋“ค์ด ์ถ”์ฒœํ•œ ๊ฒƒ์ž…๋‹ˆ๋‹ค.
์˜์ƒ ๊ธธ์ด:
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๋„์›€์ด ๋˜์—ˆ๋‚˜์š”?

์ฃผ์š” ๊ฐœ๋…

์งˆ๋ฌธ์— ์˜ฌ๋ฐ”๋ฅด๊ฒŒ ๋‹ตํ•˜๊ธฐ ์œ„ํ•ด ๋ฐ˜๋“œ์‹œ ์ดํ•ดํ•ด์•ผ ํ•˜๋Š” ํ•ต์‹ฌ ๊ฐœ๋…๋“ค์€ ๋‹ค์Œ๊ณผ ๊ฐ™์Šต๋‹ˆ๋‹ค.

Unit Circle and Angle Measurement

The unit circle is a circle with radius 1 centered at the origin, used to define trigonometric functions for all angles. Angles are measured in radians from 0 to 2ฯ€ for one full rotation, helping locate sine values on the circle.
์ถ”์ฒœ ์˜์ƒ:
06:11
Introduction to the Unit Circle

Sine Function and Its Range

The sine function gives the y-coordinate of a point on the unit circle corresponding to an angle ฮธ. Its values range between -1 and 1, so any sine value must lie within this interval to have real solutions.
์ถ”์ฒœ ์˜์ƒ:
4:22
Domain and Range of Function Transformations

Solving Trigonometric Equations

To solve equations like sin ฮธ = -โˆš2/2, identify all angles ฮธ within the given interval where sine equals that value. Since sine is negative in the third and fourth quadrants, find corresponding reference angles and adjust for these quadrants.
์ถ”์ฒœ ์˜์ƒ:
4:34
How to Solve Linear Trigonometric Equations