Solve each equation on the interval [0, 2𝝅). Use exact values where possible or give approximate solutions correct to four decimal places. sin 2x + cos x = 0
Table of contents
- 0. Review of College Algebra4h 45m
- 1. Measuring Angles40m
- 2. Trigonometric Functions on Right Triangles2h 5m
- 3. Unit Circle1h 19m
- 4. Graphing Trigonometric Functions1h 19m
- 5. Inverse Trigonometric Functions and Basic Trigonometric Equations1h 41m
- 6. Trigonometric Identities and More Equations2h 34m
- 7. Non-Right Triangles1h 38m
- 8. Vectors2h 25m
- 9. Polar Equations2h 5m
- 10. Parametric Equations1h 6m
- 11. Graphing Complex Numbers1h 7m
5. Inverse Trigonometric Functions and Basic Trigonometric Equations
Linear Trigonometric Equations
Problem 6.RE.37
Textbook Question
Solve each equation over the interval [0, 2π). Write solutions as exact values or to four decimal places, as appropriate.
2 tan x -1 = 0
Verified step by step guidance1
Start with the given equation: \(2 \tan x - 1 = 0\).
Isolate \(\tan x\) by adding 1 to both sides and then dividing by 2, giving \(\tan x = \frac{1}{2}\).
Recall that \(\tan x = \frac{\sin x}{\cos x}\) and that the tangent function has a period of \(\pi\), so solutions repeat every \(\pi\) radians.
Find the principal solution \(x_1\) by taking the arctangent: \(x_1 = \arctan\left(\frac{1}{2}\right)\), which will be in the first quadrant since \(\frac{1}{2}\) is positive.
Find the second solution \(x_2\) in the interval \([0, 2\pi)\) by adding \(\pi\) to the principal solution: \(x_2 = x_1 + \pi\). These two values are the solutions to the equation in the given interval.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Solving Trigonometric Equations
Solving trigonometric equations involves isolating the trigonometric function and finding all angle values within a given interval that satisfy the equation. This often requires algebraic manipulation and understanding the periodic nature of trig functions.
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Properties of the Tangent Function
The tangent function, tan(x), is periodic with period π and is undefined at odd multiples of π/2. Knowing its period and behavior helps find all solutions within the interval by adding integer multiples of π to the principal solution.
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Introduction to Tangent Graph
Interval Notation and Solution Restrictions
When solving trig equations over a specific interval like [0, 2π), solutions must be restricted to that range. This means identifying all valid solutions within the interval and expressing them as exact values or decimal approximations as required.
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i & j Notation
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