Inverse Trigonometric Functions

  • Introducing inverse trigonometric functions
  • Difference between trigonometric and inverse trigonometric functions
  • Notation: sin-1(x), cos-1(x), tan-1(x), etc.
  • Domain and range of inverse trigonometric functions
  • Restrictions on the domain to ensure one-to-oneness

Inverse Functions

  • Recap of inverse functions
  • Definition of inverse functions in terms of mapping
  • Conditions for two functions to be inverses of each other
  • Graphical representation of inverse functions

Inverse Trigonometric Definitions

  • Definitions of inverse trigonometric functions using triangles
    • sin-1(x) as an angle whose sine is x
    • cos-1(x) as an angle whose cosine is x
    • tan-1(x) as an angle whose tangent is x
  • Inverse functions of sec, csc, and cot

Understanding Restrictions

  • Understanding the restrictions on the domain of inverse trigonometric functions
  • Restricted domains for sine, cosine, and tangent
  • Importance of restricted domains for defining inverse functions
  • Examples of restricted domains

Evaluating Inverse Trigonometric Functions

  • Understanding the process of evaluating inverse trigonometric functions
  • Using special triangles to evaluate inverse trigonometric functions
  • Using unit circle to evaluate inverse trigonometric functions
  • Evaluating inverse trigonometric functions with the help of identities and formulas

Graphs of Inverse Trigonometric Functions

  • Understanding the graphs of inverse trigonometric functions
  • Graphs of sin-1(x), cos-1(x), and tan-1(x)
  • Understanding the inverse relationship between trigonometric and inverse trigonometric functions

Properties of Inverse Trigonometric Functions

  • Recap of properties of inverse functions
  • Similar properties for inverse trigonometric functions
  • Principal values and periodicity of inverse trigonometric functions
  • Review of special values and domains for inverse trigonometric functions

Derivatives of Inverse Trigonometric Functions

  • Finding derivatives of inverse trigonometric functions
  • Derivatives of sin-1(x), cos-1(x), and tan-1(x)
  • Steps to find derivatives using inverse trigonometric formulas
  • Understanding the chain rule in differentiation

Integrals of Inverse Trigonometric Functions

  • Integrating inverse trigonometric functions

  • Integrals of sin-1(x), cos-1(x), and tan-1(x)

  • Approaches to integrating inverse trigonometric functions

  • Evaluating indefinite integrals and solving definite integrals Inverse Trigonometric Functions - Difference of two inverses of tangent

  • Definition of inverse tangent function: tan-1(x) as an angle whose tangent is x

  • Let’s consider two angles, A and B, such that tan(A) = p and tan(B) = q

  • Difference between the two angles can be expressed as: A - B = tan-1(p) - tan-1(q)

  • Using the trigonometric identity tan(A - B) = (tan(A) - tan(B)) / (1 + tan(A) tan(B))

  • Substituting the values, we get: A - B = tan-1((p - q) / (1 + pq))

  • This formula gives us the difference between two angles whose tangents are given

    Example:
    Find the value of tan-1(3) - tan-1(2)
    Solution:
    Using the formula, we have: tan-1(3) - tan-1(2) = tan-1((3 - 2) / (1 + (3)(2)))
    Simplifying further, we get: tan-1(1/7)
    Inverse Trigonometric Functions - Addition of two inverses of tangent
  • Similar to the difference formula, we can also derive the formula for addition of two inverses of tangent

  • Let A and B be two angles such that tan(A) = p and tan(B) = q

  • The sum of the two angles can be expressed as: A + B = tan-1(p) + tan-1(q)

  • Using the trigonometric identity tan(A + B) = (tan(A) + tan(B)) / (1 - tan(A) tan(B))

  • Substituting the values, we get: A + B = tan-1((p + q) / (1 - pq))

  • This formula gives us the sum of two angles whose tangents are given

    Example:
    Find the value of tan-1(1/4) + tan-1(2/7)
    Solution:
    Using the formula, we have: tan-1(1/4) + tan-1(2/7) = tan-1(((1/4) + (2/7)) / (1 - ((1/4)(2/7))))
    Simplifying further, we get: tan-1(9/26)
    Inverse Trigonometric Functions - Expressions in terms of cotangent
  • Cotangent is the reciprocal of tangent, i.e., cot(x) = 1 / tan(x)

  • We can express the inverse trigonometric functions of tangent in terms of cotangent

  • The expressions are as follows:

    • cot-1(x) = tan-1(1 / x)
    • tan-1(x) = cot-1(1 / x)
    • cot-1(x) = π/2 - tan-1(x)
    • tan-1(x) = π/2 - cot-1(x)
      Example:
      Simplify the expression cot-1(√3)
      Solution:
      Using the formula, we have: cot-1(√3) = tan-1(1 / √3)
      Simplifying further, we get: cot-1(√3) = tan-1(√3/3)
      Inverse Trigonometric Functions - Expressions involving multiple angles
  • Inverse trigonometric functions can have expressions involving multiple angles

  • Let’s consider the formula for arcsin:

    • sin(A + B) = sin(A) cos(B) + cos(A) sin(B)
    • Replacing A and B with inverse sine functions, we get:
      • sin(sin-1(x) + sin-1(y)) = xy + √(1 - x^2) √(1 - y^2)
  • Similar formulas can be derived for other inverse trigonometric functions as well

    Example:
    Find the value of sin(sin-1(1/3) + sin-1(2/5))
    Solution:
    Using the formula, we have: sin(sin-1(1/3) + sin-1(2/5)) = (1/3)(2/5) + √(1 - (1/3)^2) √(1 - (2/5)^2)
    Simplifying further, we get: sin(sin-1(1/3) + sin-1(2/5)) = 2/15 + √(8/9) √(21/25)
    Inverse Trigonometric Functions - Max and min values
  • The domain of inverse trigonometric functions is restricted to ensure one-to-oneness

  • As a result, the range of inverse trigonometric functions is limited

  • The range of inverse sine function (sin-1(x)) is [-π/2, π/2]

  • The range of inverse cosine function (cos-1(x)) is [0, π]

  • The range of inverse tangent function (tan-1(x)) is [-π/2, π/2]

  • These ranges determine the maximum and minimum values that the inverse trigonometric functions can take

    Example:
    Find the maximum and minimum values of sin-1(x)
    Solution:
    The maximum value of sin-1(x) is π/2, and the minimum value is -π/2
    Inverse Trigonometric Functions - Graphs
  • Graphs of inverse trigonometric functions help visualize their behavior

  • Graph of y = sin-1(x):

    • Domain: [-1, 1]
    • Range: [-π/2, π/2]
    • As x approaches -1 or 1, the corresponding y values approach -π/2 and π/2 respectively
    • The graph is symmetric about the line y = x
  • Graphs of cos-1(x) and tan-1(x) have similar characteristics

    Example:
    Draw the graph of y = cos-1(x)
    Solution:
    Using the characteristics of the graph, we can plot points and sketch the graph
    Inverse Trigonometric Functions - Difference of two inverses of tangent
  • Definition of inverse tangent function: tan-1(x) as an angle whose tangent is x

  • Let’s consider two angles, A and B, such that tan(A) = p and tan(B) = q

  • Difference between the two angles can be expressed as: A - B = tan-1(p) - tan-1(q)

  • Using the trigonometric identity tan(A - B) = (tan(A) - tan(B)) / (1 + tan(A) tan(B))

  • Substituting the values, we get: A - B = tan-1((p - q) / (1 + pq))

  • This formula gives us the difference between two angles whose tangents are given

    Example:
    Find the value of tan-1(3) - tan-1(2)
    Solution:
    Using the formula, we have: tan-1(3) - tan-1(2) = tan-1((3 - 2) / (1 + (3)(2)))
    Simplifying further, we get: tan-1(1/7)
    Inverse Trigonometric Functions - Addition of two inverses of tangent
  • Similar to the difference formula, we can also derive the formula for addition of two inverses of tangent

  • Let A and B be two angles such that tan(A) = p and tan(B) = q

  • The sum of the two angles can be expressed as: A + B = tan-1(p) + tan-1(q)

  • Using the trigonometric identity tan(A + B) = (tan(A) + tan(B)) / (1 - tan(A) tan(B))

  • Substituting the values, we get: A + B = tan-1((p + q) / (1 - pq))

  • This formula gives us the sum of two angles whose tangents are given

    Example:
    Find the value of tan-1(1/4) + tan-1(2/7)
    Solution:
    Using the formula, we have: tan-1(1/4) + tan-1(2/7) = tan-1(((1/4) + (2/7)) / (1 - ((1/4)(2/7))))
    Simplifying further, we get: tan-1(9/26)
    Inverse Trigonometric Functions - Expressions in terms of cotangent
  • Cotangent is the reciprocal of tangent, i.e., cot(x) = 1 / tan(x)

  • We can express the inverse trigonometric functions of tangent in terms of cotangent

  • The expressions are as follows:

    • cot-1(x) = tan-1(1 / x)
    • tan-1(x) = cot-1(1 / x)
    • cot-1(x) = π/2 - tan-1(x)
    • tan-1(x) = π/2 - cot-1(x)
      Example:
      Simplify the expression cot-1(√3)
      Solution:
      Using the formula, we have: cot-1(√3) = tan-1(1 / √3)
      Simplifying further, we get: cot-1(√3) = tan-1(√3/3)
      Inverse Trigonometric Functions - Expressions involving multiple angles
  • Inverse trigonometric functions can have expressions involving multiple angles

  • Let’s consider the formula for arcsin:

    • sin(A + B) = sin(A) cos(B) + cos(A) sin(B)
    • Replacing A and B with inverse sine functions, we get:
      • sin(sin-1(x) + sin-1(y)) = xy + √(1 - x^2) √(1 - y^2)
  • Similar formulas can be derived for other inverse trigonometric functions as well

    Example:
    Find the value of sin(sin-1(1/3) + sin-1(2/5))
    Solution:
    Using the formula, we have: sin(sin-1(1/3) + sin-1(2/5)) = (1/3)(2/5) + √(1 - (1/3)^2) √(1 - (2/5)^2)
    Simplifying further, we get: sin(sin-1(1/3) + sin-1(2/5)) = 2/15 + √(8/9) √(21/25)
    Inverse Trigonometric Functions - Max and min values
  • The domain of inverse trigonometric functions is restricted to ensure one-to-oneness

  • As a result, the range of inverse trigonometric functions is limited

  • The range of inverse sine function (sin-1(x)) is [-π/2, π/2]

  • The range of inverse cosine function (cos-1(x)) is [0, π]

  • The range of inverse tangent function (tan-1(x)) is [-π/2, π/2]

  • These ranges determine the maximum and minimum values that the inverse trigonometric functions can take

    Example:
    Find the maximum and minimum values of sin-1(x)
    Solution:
    The maximum value of sin-1(x) is π/2, and the minimum value is -π/2
    Inverse Trigonometric Functions - Graphs
  • Graphs of inverse trigonometric functions help visualize their behavior

  • Graph of y = sin-1(x):

    • Domain: [-1, 1]
    • Range: [-π/2, π/2]
    • As x approaches -1 or 1, the corresponding y values approach -π/2 and π/2 respectively
    • The graph is symmetric about the line y = x
  • Graphs of cos-1(x) and tan-1(x) have similar characteristics

    Example:
    Draw the graph of y = cos-1(x)
    Solution:
    Using the characteristics of the graph, we can plot points and sketch the graph