In Class 11 Mathematics, the 'Trigonometric Functions' chapter introduces many new identities. The 'Sum to Product' formulas (often called the C & D formulas) and the 'Multiple Angle' formulas are the most heavily used in calculus and algebra.
Sin C + Sin D: Used to convert Addition into Multiplication.
Sin 3θ: $3\sin\theta - 4\sin^3\theta$.
These formulas are used to convert the sum or difference of two sine/cosine functions into a multiplication (product) format.
This is a multiple-angle identity used to break down an angle that is multiplied by 3 into single angles.
(Trick to remember: Think of the number 34. The 3 comes first, then the 4 with the cube!)
The formula is: Sin C + Sin D = 2 Sin((C+D)/2) Cos((C-D)/2).
What is the Value of tan 15°?
tan 15° = 2−√3 ≈ 0.2679. Derived using tan(45°−30°) = (1−1/√3)/(1+1/√3) = 2−√3. Full step-by-step proof included.
tan 2x Formula – Derivation and Examples
Learn the complete tan 2x double angle formula. Understand its derivation from sin and cos double angle formulas with solved examples.
What is the formula for tan(3x)?
Learn the tan 3x formula in trigonometry. See the clear equation, how to memorize it, and its derivation using the compound angle tan(A+B) formula.
What is the Value of tan 90°? — Undefined (Not Defined)
tan 90° is undefined (not defined). sin 90°=1, cos 90°=0, and tan=sin/cos=1/0=undefined. As angle→90°, tan→∞. Full explanation with unit circle.
Time Conversions – Hours, Weeks, Months
Learn all important time conversions: 1 hour in seconds, 1 year in weeks, 9 months in weeks, 444 days in months, 1 inch in mm.
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