Maths · Class 11 · Chapter 3
Trigonometric Functions
13 lessons 119 min 2 simulations
This chapter turns the triangle ratios of earlier classes into functions defined for every real number. It measures angles in degrees and radians, defines sine and cosine as the coordinates of a point on the unit circle, studies all six functions with their signs, domains, ranges and graphs, and derives the sum, difference, multiple angle and sum-to-product identities used throughout calculus and coordinate geometry.
What the exam asks
JEE Main uses this chapter everywhere: degree and radian conversion with l = rθ, the value of a function at a large or negative angle, finding all six values from one given value and a quadrant, and above all simplifying expressions with the compound, allied, double angle and sum-to-product identities. Marks are lost on signs in the wrong quadrant, on using l = rθ with θ in degrees, on writing sin (x + y) as sin x + sin y, and on forgetting where tan, sec, cot and cosec are undefined.
Lessons
13 lessons · 119 min
1Angles and degree measureNCERT §3.2.18 min2Radian measure and arc lengthNCERT §3.2.211 min 1 sim3Converting between degrees and radiansNCERT §3.2.47 min4Sine and cosine on the unit circleNCERT §3.312 min 1 sim5The other four trigonometric functionsNCERT §3.38 min6Signs in the four quadrantsNCERT §3.3.17 min7Domain, range and graphsNCERT §3.3.29 min8Sine and cosine of sums and differencesNCERT §3.48 min9Allied anglesNCERT §3.48 min10Tangent and cotangent of sumsNCERT §3.48 min11Double and triple angle formulasNCERT §3.48 min12Sum and product formulasNCERT §3.48 min13Chapter reviewMust-know facts, traps and formulas17 min