Evaluate: cos 26+ cos640. sin26° + sin 170 30 cos 72⁰ 30¹
Answers
Answered by
7
(i)
cos72
o
sin18
o
=
cos72
o
sin(90−72)
o
=
cos72
o
cos72
o
=1
Hence, the value is 1
(ii)
cot64
o
tan26
o
=
cot64
o
tan(90−64)
o
=
cot64
o
cot64
o
=1
Hence, the value is 1
(iii) cos48
o
−sin42
o
=cos(90−42)
o
−sin42
o
=sin42
o
−sin42
o
=0
Hence, the value is 0
(iv) csc 31
o
−sec59
o
=csc (90−59)
o
−sec59
o
=sec59
o
−sec59
o
=0
Hence, the value is 0
Answered by
1
Solution
verified
Verified by Toppr
(i)
cos72
o
sin18
o
=
cos72
o
sin(90−72)
o
=
cos72
o
cos72
o
=1
Hence, the value is 1
(ii)
cot64
o
tan26
o
=
cot64
o
tan(90−64)
o
=
cot64
o
cot64
o
=1
Hence, the value is 1
(iii) cos48
o
−sin42
o
=cos(90−42)
o
−sin42
o
=sin42
o
−sin42
o
=0
Hence, the value is 0
(iv) csc 31
o
−sec59
o
=csc (90−59)
o
−sec59
o
=sec59
o
−sec59
o
=0
Hence, the value is 0
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