Book: NCERT - Mathematics
Chapter: 8. Introduction to Trigonometry
Subject: Maths - Class 10th
Q. No. 5 of Exercise 8.1
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5
Given sec 
calculate all other trigonometric ratios
Consider a right-angle triangle ΔABC, right-angled at point B
sec
= 
= 
If AC is 13k, AB will be 12k, where k is a positive integer.
Applying Pythagoras theorem in ΔABC, we obtain
(AC)2 = (AB)2 + (BC)2
(13k)2 = (12k)2 + (BC)2
169k2 = 144k2 + BC2
25k2 = BC2
BC = 5k
Sin 
= 
= 
= 
Cos θ = 
= 
= 
Tan θ = 
= 
= 
Cot θ = 
= 
= 
Cosec θ = 
= 
= 
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