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NCERT Solutions for Class 11 Math Ch-3: Trigonometric Functions

NCERT Solutions for Class 11 Maths Chapter 3 Trigonometric Functions covers angle measurement in degrees and radians, trigonometric ratios and identities, and the solution of trigonometric equations.

Overview of Topics & Subtopics

Important Questions and Answers

Q1: What is the relationship between radian and degree measure of an angle?
Answer: The relationship between radian and degree measure is given by π radians = 180°, which is used to convert angles between the two systems; for example, 1 radian equals approximately 57.3°.
Q2: State the fundamental trigonometric identity involving sine and cosine.
Answer: The fundamental trigonometric identity is sin²θ + cos²θ = 1, valid for all values of θ, and it forms the basis for deriving many other trigonometric identities.
Q3: Write the formulas for sin(A + B) and cos(A + B).
Answer: The sum formulas are: sin(A + B) = sinA cosB + cosA sinB, and cos(A + B) = cosA cosB − sinA sinB, which are used to find trigonometric values of the sum of two angles.
Q4: How are the signs of trigonometric functions determined in the four quadrants?
Answer: In the first quadrant, all trigonometric functions are positive. In the second quadrant, only sine and cosecant are positive. In the third quadrant, only tangent and cotangent are positive. In the fourth quadrant, only cosine and secant are positive (often remembered by the mnemonic 'All Silver Tea Cups').
Q5: What is the general solution of the equation sinθ = 0?
Answer: The general solution of sinθ = 0 is θ = nπ, where n is any integer, since sine equals zero at every integer multiple of π.
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Class 11 › Mathematics › Trigonometric Functions
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