Learn All Concepts of Chapter 2 Class 11 Relations and Function - FREE. Check - Trigonometry Class 11 - All Concepts

Last updated at Feb. 12, 2020 by Teachoo
Learn All Concepts of Chapter 2 Class 11 Relations and Function - FREE. Check - Trigonometry Class 11 - All Concepts
Transcript
Ex 3.2, 7 Find the value of the trigonometric function cosec (–1410°) cosec (–1410°) = –cosec (1410°) = –cosec ("1410 × " 𝜋/180) = –cosec (47𝜋/6) = –cosec ("7" 5/6 𝜋) = –cosec ("8π – " 1/6 "π" ) As sin(−x) = −sin x, So, cosec(−x) = −cosec x Rough So, 47/6 = 7 5/6 = 7 + 5/6 or 8 – 1/6 We take 8 – 1/6 as it is even Values of cosec x repeats after an interval of 2π , Hence ignoring 4 × (2π) i.e. 8π = –cosec ("–" 1/6 " π" ) = –cosec ("– " 1/6 " × 180" °) = –cosec (–30°) = –(–cosec 30°) = cosec 30° = 1/sin〖30°〗 = 1/(( 1/2 ) ) = 2/1 = 2 As sin(−x) = −sin x, So, cosec(−x) = −cosec x
Finding Value of trignometric functions, given angle
Value of sin, cos, tan repeats after 2π
Shifting angle by π/2, π, 3π/2 , 2π
Example 8
Ex 3.2, 9 Important
Ex 3.2, 8 Important
Ex 3.2, 10 Important
Example 9 Important
Ex 3.2, 6
Ex 3.2, 7 Important You are here
Example 10
Ex 3.3, 1
Ex 3.3, 2 Important
Ex 3.3, 3 Important
Ex 3.3, 4
Ex 3.3, 8 Important
Ex 3.3, 9 Important
Find values of sin 18, cos 18, cos 36, sin 36, sin 54, cos 54 Important
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