Inverse Trigonometric Functions
Relation between inverse(x) and inverse(-x)
- Inverse Trigonometric Functions deal with the angles formed when trigonometric ratios are given.
- These functions are defined as the inverses of the trigonometric functions.
Properties of Inverse Trigonometric Functions
- The input of an inverse trigonometric function is the ratio of two sides in a right triangle.
- The output of an inverse trigonometric function is the angle opposite to that ratio.
Inverse Trigonometric Functions in terms of Sine
- sin^(-1)(x) represents the angle whose sine is x.
- The range of sin^(-1)(x) is [-π/2, π/2].
Inverse Trigonometric Functions in terms of Cosine
- cos^(-1)(x) represents the angle whose cosine is x.
- The range of cos^(-1)(x) is [0, π].
Inverse Trigonometric Functions in terms of Tangent
- tan^(-1)(x) represents the angle whose tangent is x.
- The range of tan^(-1)(x) is [-π/2, π/2].
Relation between inverse(x) and inverse(-x)
- For any real number x, sin^(-1)(-x) = -sin^(-1)(x).
- For any real number x, cos^(-1)(-x) = π - cos^(-1)(x).
- For any real number x, tan^(-1)(-x) = -tan^(-1)(x).
Domain and Range of Inverse Trigonometric Functions
- The domain of an inverse trigonometric function is the range of the corresponding trigonometric function.
- The range of an inverse trigonometric function is the domain of the corresponding trigonometric function.
Domain and Range of sin^(-1)(x)
- The domain of sin^(-1)(x) is [-1, 1].
- The range of sin^(-1)(x) is [-π/2, π/2].
Domain and Range of cos^(-1)(x)
- The domain of cos^(-1)(x) is [-1, 1].
- The range of cos^(-1)(x) is [0, π].
Domain and Range of tan^(-1)(x)
- The domain of tan^(-1)(x) is (-∞, ∞).
- The range of tan^(-1)(x) is (-π/2, π/2).
Properties of Inverse Trigonometric Functions
- The sum, difference, and product of two inverse trigonometric functions often involve identities and simplifications.
- The composition of two inverse trigonometric functions can simplify to simpler forms.
Property 1: sin^(-1)(x) + cos^(-1)(x) = π/2
Property 2: sin^(-1)(x) - cos^(-1)(x) = π/2
Property 3: tan^(-1)(x) * cot^(-1)(x) = 1
Property 4: sin^(-1)(x) = cos^(-1)(√(1-x^2))
Property 5: cos(2tan^(-1)(x)) = 1/(1+x^2)
Property 6: sin(2sin^(-1)(x)) = 2x/√(1-x^2)
Simplifying Compositions of Inverse Trigonometric Functions
- Compositions of inverse trigonometric functions typically simplify to simpler forms.
- These simplifications can be derived using trigonometric identities.
Example: sin^(-1)(sin(x))
- The composition of sin^(-1)(sin(x)) can be simplified.
- If -π/2 ≤ x ≤ π/2, then sin^(-1)(sin(x)) simplifies to x.
- If x < -π/2 or x > π/2, then sin^(-1)(sin(x)) simplifies to π - x.
Example: cos^(-1)(cos(x))
- The composition of cos^(-1)(cos(x)) can be simplified.
- If 0 ≤ x ≤ π, then cos^(-1)(cos(x)) simplifies to x.
- If x < 0 or x > π, then cos^(-1)(cos(x)) simplifies to -x.
Evaluating Inverse Trigonometric Functions
- The values of inverse trigonometric functions can be evaluated using special triangles or reference angles.
- Calculators and tables can also be used to find approximate values.
Example: Evaluate sin^(-1)(1/2)
- Using special triangles, we know that sin^(-1)(1/2) = π/6 or 30 degrees.
Example: Evaluate cos^(-1)(-1/2)
- Using special triangles, we know that cos^(-1)(-1/2) = 2π/3 or 120 degrees.
Example: Evaluate tan^(-1)(√3)
- Using reference angles, we know that tan^(-1)(√3) = π/3 or 60 degrees.
Graphs of Inverse Trigonometric Functions
- The graphs of inverse trigonometric functions can be obtained by reflecting the graphs of the corresponding trigonometric functions in the line y = x.
- The domain of the inverse trigonometric functions becomes the range of the corresponding trigonometric functions.
Graph of y = sin^(-1)(x)
- The graph of y = sin^(-1)(x) is a quarter unit circle in the first and second quadrants.
- The domain is [-1, 1] and the range is [-π/2, π/2].
Graph of y = cos^(-1)(x)
- The graph of y = cos^(-1)(x) is a quarter unit circle in the first and fourth quadrants.
- The domain is [-1, 1] and the range is [0, π].
Graphs of Inverse Trigonometric Functions (contd.)
Graph of y = tan^(-1)(x)
- The graph of y = tan^(-1)(x) covers the entire plane, except for the vertical asymptotes x = π/2 and x = -π/2.
- The domain is (-∞, ∞) and the range is (-π/2, π/2).
Graph of y = cot^(-1)(x)
- The graph of y = cot^(-1)(x) covers the entire plane, except for the vertical asymptotes x = 0 and x = π.
- The domain is (-∞, ∞) and the range is (0, π).
Inverse Trigonometric Functions in Terms of Other Functions
- Inverse trigonometric functions can be expressed in terms of other trigonometric functions.
- These expressions can be derived using trigonometric identities and algebraic manipulations.
Expressing sin^(-1)(x) in terms of cos^(-1)(x)
- By using the identity sin^2(x) + cos^2(x) = 1, we can derive an expression for sin^(-1)(x) in terms of cos^(-1)(x) as sin^(-1)(x) = π/2 - cos^(-1)(x).
Expressing cos^(-1)(x) in terms of sin^(-1)(x)
- By using the identity sin^2(x) + cos^2(x) = 1, we can derive an expression for cos^(-1)(x) in terms of sin^(-1)(x) as cos^(-1)(x) = π/2 - sin^(-1)(x).
Inverse Trigonometric Functions in Terms of Other Functions (contd.)
Expressing tan^(-1)(x) in terms of cos^(-1)(x)
- By using the identity tan(x) = sin(x)/cos(x), we can derive an expression for tan^(-1)(x) in terms of cos^(-1)(x) as tan^(-1)(x) = sin^(-1)(x/sqrt(1+x^2)).
Expressing cot^(-1)(x) in terms of sin^(-1)(x)
- By using the identity cot(x) = cos(x)/sin(x), we can derive an expression for cot^(-1)(x) in terms of sin^(-1)(x) as cot^(-1)(x) = sin^(-1)(1/x).
Applications of Inverse Trigonometric Functions
- Inverse trigonometric functions have various applications in mathematics and physics.
- They are used to solve problems involving angles, distances, and coordinates.
Example: Finding the angle of elevation
- Inverse trigonometric functions are used to find the angle of elevation in problems involving heights or distances.
Example: Solving for unknown sides in right triangles
- By applying inverse trigonometric functions, we can find the lengths of the unknown sides in right triangles.
Applications of Inverse Trigonometric Functions (contd.)
Example: Calculating coordinates
- Inverse trigonometric functions are used to calculate the coordinates of a point given its distance and angle from the origin.
Example: Solving trigonometric equations
- Inverse trigonometric functions are used to solve trigonometric equations involving unknown angles.
Inverse Trigonometric Functions - Relation between inverse(x) and inverse(-x)
- For any real number x, sin^(-1)(-x) = -sin^(-1)(x).
- For any real number x, cos^(-1)(-x) = π - cos^(-1)(x).
- For any real number x, tan^(-1)(-x) = -tan^(-1)(x).
Example: Find sin^(-1)(-0.5)
- sin^(-1)(-0.5) is equivalent to -sin^(-1)(0.5).
- Using a calculator, we find that sin^(-1)(0.5) is approximately 0.524.
- Therefore, sin^(-1)(-0.5) is approximately -0.524.
Example: Find cos^(-1)(-0.8)
- cos^(-1)(-0.8) is equivalent to π - cos^(-1)(0.8).
- Using a calculator, we find that cos^(-1)(0.8) is approximately 0.643.
- Therefore, cos^(-1)(-0.8) is approximately π - 0.643 ≈ 2.498.
Example: Find tan^(-1)(-2)
- tan^(-1)(-2) is equivalent to -tan^(-1)(2).
- Using a calculator, we find that tan^(-1)(2) is approximately 1.107.
- Therefore, tan^(-1)(-2) is approximately -1.107.
Inverse Trigonometric Functions - Domain and Range
- The domain of an inverse trigonometric function is the range of the corresponding trigonometric function.
- The range of an inverse trigonometric function is the domain of the corresponding trigonometric function.
Domain and Range of sin^(-1)(x)
- The domain of sin^(-1)(x) is [-1, 1].
- The range of sin^(-1)(x) is [-π/2, π/2].
Domain and Range of cos^(-1)(x)
- The domain of cos^(-1)(x) is [-1, 1].
- The range of cos^(-1)(x) is [0, π].
Domain and Range of tan^(-1)(x)
- The domain of tan^(-1)(x) is (-∞, ∞).
- The range of tan^(-1)(x) is (-π/2, π/2).
Example: Find the domain and range of sin^(-1)(x^2)
- The domain is [0, 1] because x^2 can only be between 0 and 1.
- The range is [0, π/2] because sin^(-1)(x) has a range of [-π/2, π/2].
Inverse Trigonometric Functions - Simplifying Compositions
- Compositions of inverse trigonometric functions typically simplify to simpler forms.
- These simplifications can be derived using trigonometric identities.
Example: Simplify sin^(-1)(sin(x))
- If -π/2 ≤ x ≤ π/2, then sin^(-1)(sin(x)) simplifies to x.
- If x < -π/2 or x > π/2, then sin^(-1)(sin(x)) simplifies to π - x.
Example: Simplify cos^(-1)(cos(x))
- If 0 ≤ x ≤ π, then cos^(-1)(cos(x)) simplifies to x.
- If x < 0 or x > π, then cos^(-1)(cos(x)) simplifies to -x.
Example: Simplify tan^(-1)(tan(x))
- If -π/2 ≤ x ≤ π/2, then tan^(-1)(tan(x)) simplifies to x.
- If x < -π/2 or x > π/2, then tan^(-1)(tan(x)) simplifies to x - π.
Example: Simplify sin^(-1)(cos(x))
- There is no simplification for sin^(-1)(cos(x)). It remains as sin^(-1)(cos(x)).
Inverse Trigonometric Functions - Evaluating Values
- The values of inverse trigonometric functions can be evaluated using special triangles or reference angles.
- Calculators and tables can also be used to find approximate values.
Example: Evaluate sin^(-1)(1/2)
- Using special triangles, we know that sin^(-1)(1/2) is equal to π/6 or approximately 0.524.
Example: Evaluate cos^(-1)(-0.5)
- Using special triangles, we know that cos^(-1)(-0.5) is equal to π/3 or approximately 1.047.
Example: Evaluate tan^(-1)(√3)
- Using reference angles, we know that tan^(-1)(√3) is equal to π/3 or approximately 1.047.
Example: Evaluate sin^(-1)(0)
- The input of sin^(-1)(x) is the ratio of two sides in a right triangle.
- Since sin(0) = 0, sin^(-1)(0) is equal to 0.
Inverse Trigonometric Functions - Graphs
- The graphs of inverse trigonometric functions can be obtained by reflecting the graphs of the corresponding trigonometric functions in the line y = x.
- The domain of the inverse trigonometric functions becomes the range of the corresponding trigonometric functions.
Graph of y = sin^(-1)(x)
- The graph of y = sin^(-1)(x) is a quarter unit circle in the first and second quadrants.
- The domain is [-1, 1] and the range is [-π/2, π/2].
Graph of y = cos^(-1)(x)
- The graph of y = cos^(-1)(x) is a quarter unit circle in the first and fourth quadrants.
- The domain is [-1, 1] and the range is [0, π].
Graph of y = tan^(-1)(x)
- The graph of y = tan^(-1)(x) covers the entire plane, except for the vertical asymptotes x = π/2 and x = -π/2.
- The domain is (-∞, ∞) and the range is (-π/2, π/2).
Inverse Trigonometric Functions - Graphs (contd.)
Graph of y = cot^(-1)(x)
- The graph of y = cot^(-1)(x) covers the entire plane, except for the vertical asymptotes x = 0 and x = π.
- The domain is (-∞, ∞) and the range is (0, π).
Example: Sketch the graph of y = sin^(-1)(x)
- We know that the graph is a quarter unit circle in the first and second quadrants.
- The domain is [-1, 1] and the range is [-π/2, π/2].
Example: Sketch the graph of y = tan^(-1)(x)
- The graph covers the entire plane, except for the vertical asymptotes x = π/2 and x = -π/2.
- The domain is (-∞, ∞) and the range is (-π/2, π/2).
Example: Sketch the graph of y = cos^(-1)(x)
- The graph is a quarter unit circle in the first and fourth quadrants.
- The domain is [-1, 1] and the range is [0, π].
Inverse Trigonometric Functions - Other Expressions
- Inverse trigonometric functions can be expressed in terms of other trigonometric functions.
- These expressions can be derived using trigonometric identities and algebraic manipulations.
Expressing sin^(-1)(x) in terms of cos^(-1)(