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Example 6 - Chapter 3 Class 11 Trigonometric Functions (Term 2)
Last updated at Feb. 12, 2020 by Teachoo
Examples
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Example 6 Important You are here
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Example 20 Deleted for CBSE Board 2023 Exams
Example 21 Deleted for CBSE Board 2023 Exams
Example 22 Important Deleted for CBSE Board 2023 Exams
Example 23 Deleted for CBSE Board 2023 Exams
Example 24 Important Deleted for CBSE Board 2023 Exams
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Chapter 3 Class 11 Trigonometric Functions
Serial order wise
- Ex 3.1
- Ex 3.2
- Ex 3.3
- Ex 3.4
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Examples
- Miscellaneous
Transcript
Example 6 If cos𝑥 = – 3/5 , x lies in third quadrant, find the values of other five trigonometric functions. Since x is in lllrd Quadrant sin and cos will be negative But tan will be positive Given cos x = (−3)/5 We know that sin2 x + cos2 x = 1 sin2 x + ((−3)/5)^2 = 1 sin2 x + 9/25 = 1 sin2 x = 1 – 9/25 sin2 x = (25 − 9)/25 sin2 x = (25 − 9)/25 sin2x = 16/25 sin x = ±√(16/25) sin x = ± 4/5 Since, x is in lllrd Quadrant And sin x is negative lllrd Quadrant ∴ sin x = −𝟒/𝟓 tan x = sin𝑥/cos𝑥 = (− 4/5)/(− 3/5) = (−4)/5 × 5/(−3) = 𝟒/𝟑 cot x = 1/tan𝑥 = 1/(4/3) = 𝟑/𝟒 cosec x = 1/sin𝑥 = 1/(− 4/5) = (−𝟓)/𝟒 sec x = 1/cos𝑥 = 1/((−3)/5) = 5/(−3) = (−𝟓)/𝟑
