Angle Sum Identities are mathematical formulas used in trigonometry to find the sine, cosine, and tangent of the sum of two angles. These identities are essential for simplifying expressions and solving equations involving trigonometric functions. The primary identities are: 1. sin(A + B) = sin(A)cos(B) + cos(A)sin(B) 2. cos(A + B) = cos(A)cos(B) - sin(A)sin(B) 3. tan(A + B) = (tan(A) + tan(B)) / (1 - tan(A)tan(B) These identities help in various applications, including physics, engineering, and computer graphics. Understanding these identities allows for easier manipulation of trigonometric expressions and aids in solving problems involving angles. They are particularly useful in calculus and analytical geometry, where angle relationships play a crucial role. By applying these identities, one can break down complex problems into simpler parts, making calculations more manageable.