1
You visited us
1
times! Enjoying our articles?
Unlock Full Access!
Byju's Answer
Standard XI
Mathematics
Trigonometric Ratios of Allied Angles
Evaluate co...
Question
Evaluate
cos
65
∘
sin
18
∘
cos
58
∘
cos
72
∘
sin
25
∘
sin
32
∘
Open in App
Solution
Using trigonometric ratios of complementary angles, we get
cos
65
∘
=
cos
(
90
∘
−
25
∘
)
=
sin
25
∘
,
sin
18
∘
=
sin
(
90
∘
−
72
∘
)
=
cos
72
∘
cos
58
∘
=
cos
(
90
∘
−
32
∘
)
=
sin
32
∘
.
∴
cos
65
∘
sin
18
∘
cos
58
∘
cos
72
∘
sin
25
∘
sin
32
∘
=
sin
25
∘
cos
72
∘
sin
32
∘
cos
72
∘
sin
25
∘
sin
32
∘
=
1
Suggest Corrections
0
Similar questions
Q.
Evaluate :
s
i
n
18
∘
c
o
s
72
∘
___
Q.
Evaluate :
s
i
n
18
∘
c
o
s
72
∘
=
___
Q.
Evaluate:
sin
18
∘
cos
72
∘
Q.
Evaluate
sin
18
∘
cos
72
∘
.
Q.
Evaluate:
c
o
s
58
∘
s
i
n
32
∘
+
s
i
n
22
∘
c
o
s
68
∘
.
View More
Join BYJU'S Learning Program
Grade/Exam
1st Grade
2nd Grade
3rd Grade
4th Grade
5th Grade
6th grade
7th grade
8th Grade
9th Grade
10th Grade
11th Grade
12th Grade
Submit
Related Videos
Trigonometric Ratios of Allied Angles
MATHEMATICS
Watch in App
Explore more
Trigonometric Ratios of Allied Angles
Standard XI Mathematics
Join BYJU'S Learning Program
Grade/Exam
1st Grade
2nd Grade
3rd Grade
4th Grade
5th Grade
6th grade
7th grade
8th Grade
9th Grade
10th Grade
11th Grade
12th Grade
Submit
Solve
Textbooks
Question Papers
Install app