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: |
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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: |
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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:
Example: |
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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:
Similar formulas can be derived for other inverse trigonometric functions as well
Example: |
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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):
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:
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:
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):
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 |