NCERT Solutions for Class 11 Maths Chapter 3 Trigonometric Functions Ex 3.2
Find the
values of other five trigonometric functions in Exercises 1 to 5.
Ex 3.2 Class 11 Maths Question 1.
cos x = −1/2, x lies in third quadrant.Solution.
Ex 3.2 Class 11 Maths Question 2.
sin x = 3/5, x lies in second quadrant.
Solution.
Ex 3.2 Class 11 Maths Question 3.
cot x = 3/4, x lies in third quadrant.Solution.
Ex 3.2 Class 11 Maths Question 4.
sec x = 13/5, x lies in fourth quadrant.Solution.
Ex 3.2 Class 11 Maths Question 5.
tan x = −5/12, x lies in second quadrant.Solution.
We have, tan x = -5/12
Therefore,
cot x = 1/tan x =1/(-5/12) = -12/5
Now,
sec2 x – tan2 x = 1
Therefore,
sec2 x = 1 + tan2 x
Substituting tan x = -5/12 in the formula, we
get
sec2 x = 1 + (-5/12)2
sec2 x = 1 + 25/144
=169/144
sec x = ± 13/12
Since x lies in the 2nd
quadrant, the value of sec x will be
negative.
sec x = -13/12
Therefore, cos x = 1/sec x = -12/13
Now, tan x = sin x / cos x
Therefore, sin x = tan x cos x
Hence, sin x = (-5/12) × (-12/13) = (5/13)
And cosec x = 1/sin x = 13/5
Find the values of the
trigonometric functions in Exercises 6 to 10.
Ex 3.2 Class 11 Maths Question 6.
sin 765°Solution.
Ex 3.2 Class 11 Maths Question 7.
cosec (-1410°)Solution.
Ex 3.2 Class 11 Maths Question 8.
tan (19Ï€/3)Solution.
Ex 3.2 Class 11 Maths Question 9.
sin (−11Ï€/3)Solution.
Ex 3.2 Class 11 Maths Question 10.
cot (−15Ï€/4)Solution.
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