find sin105+ cos105
Answers
Answered by
3
Answer:
Taking LHS:
sin 105° + cos 105°
cos (90° - 105°) + cos 105°
cos 15° + cos 105°
cos C + cos D = 2(cos(C+D)/2)(cos(C-D)/2)
2cos(120°/2)cos(90°/2)
2cos60°cos45°
2(1/2)cos45°
cos45°
= RHS
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I could also have converted to sine:
sin 105° + sin (90° – 105°)
sin 105° - sin 15°
sin C - sin D = 2(cos(C+D)/2)(sin(C-D)/2)
2cos(120°/2)sin(90°/2)
2cos60°sin45°
2(1/2)sin45°
sin 45°
= cos 45°
= RHS
Hope answer goes correct
Answered by
0
Answer:
1/root 2
explanation-
when you add both you get that answer
........
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