Find arcsin(0.3) and every angle in [0°, 360°) with sin x = 0.3: animated lesson
A narrated, step-by-step trigonometric equations video lesson with captions. Final answer: arcsin(0.3) = 17.45760312° (0.304692654 rad); solutions in [0°, 360°): 17.45760312°, 162.5423969°; general: x = 17.45760312° + 360°n or x = 162.5423969° + 360°n.
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Video narrated by a synthetic voice (Piper TTS, en_US-ljspeech-high voice (LJ Speech dataset, public domain)); the steps come from our maths engine and the answer was checked independently. Download MP4 (0.8 MB) · Captions (WebVTT)
Steps on screen
- 1. The problemWorked exampleFind arcsin(0.3) and every angle in [0°, 360°) with sin x = 0.3.
- 2. Step by step
- Principal value of arcsin, taken in the range [−π/2, π/2]
- Sine is also positive or negative in a second quadrant, so use x and 180° − x
- Solutions in one full turn, 0° ≤ x < 360°
- General solution, n any integer
- 3. The answer
arcsin(0.3) = 17.45760312°
- 4. Check
- Substituting each solution back: sin(17.45760312°) ≈ 0.3; sin(162.5423969°) ≈ 0.3.
Transcript
The problem. Here is the problem: Find arcsin(0.3) and every angle in [0°, 360°) with sin x equals 0.3. Find the angle whose sin is 0.3: the principal value of arcsin, every solution of sin(x) equals 0.3 in one turn, and the general solution.
Step by step. Principal value of arcsin, taken in the range [−pi/2, pi/2]. The value is not one of the standard exact values, so the angle is given as a decimal. Sine is also positive or negative in a second quadrant, so use x and 180° minus x. Solutions in one full turn, 0° less than or equal to x less than 360°. General solution, n any integer.
The answer. So the answer is arcsin(0.3) equals 17.45760312° (0.304692654 rad); solutions in [0°, 360°): 17.45760312°, 162.5423969°; general: x equals 17.45760312° plus 360°n or x equals 162.5423969° plus 360°n. An inverse trigonometric function returns one angle, the principal value. Because the trigonometric functions repeat, the equation sin(x) equals 0.3 has infinitely many solutions; the calculator lists those in one turn and the general pattern.
Check. Substituting each solution back: sin(17.45760312°) approximately 0.3; sin(162.5423969°) approximately 0.3.
About trigonometric equations
Solve trigonometric equations and give every solution.
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