Topic Details (Notes format)

How to Use Sum and Difference Identities (Sine, Cosine, Tangent)

Subject: Mathematics

Book: Maths Mastery

Trigonometric sum/difference formulas let you calculate sin(A±B), cos(A±B), tan(A±B) from sin, cos, tan of A and B. For instance, sin(A + B)=sin(A)cos(B)+cos(A)sin(B). A practical scenario: if sin(A) and cos(B) are known, you can find sin(A + B) quickly. These identities fuel transformations, equation solving, and geometry proofs. They also apply to signal processing (phase shifts) and physics (wave interference). Mastering them expands your capacity to handle angles beyond standard reference angles, bridging simpler known values to more complex angle relationships.

Practice Questions

If sin(θ) = 0.6 and θ is acute, what is cos(θ)?

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If x + 1/x = 5, what is the value of x^2 + 1/x^2?

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What is the greatest common divisor (GCD) of 36 and 48?

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What is the sum of the first 50 positive integers?

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If a = 5 and b = 12, what is the length of the hypotenuse of a right triangle?

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If the sum of three consecutive integers is 72, what are the integers?

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If sin(A) = 1/2 and A is acute, what is the value of A?

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What is the sum of all angles in a hexagon?

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If 5x - 2 = 13, what is the value of x?

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If the sides of a triangle are 6 cm, 8 cm, and 10 cm, what is the area of the triangle?

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