Trigonometric Identities Question 279
Question: $ \cos 1{}^\circ +\cos 2{}^\circ +\cos 3{}^\circ +…..+\cos 180{}^\circ = $
[Karnataka CET 2003]
Options:
A) 0
B) 1
C) -1
D) 2
Show Answer
Answer:
Correct Answer: C
Solution:
$ (\cos 1{}^\circ +\cos 179{}^\circ )+(\cos 2{}^\circ +\cos 178{}^\circ )+…. $ $ +(\cos 89{}^\circ +\cos 91{}^\circ )+\cos 90{}^\circ +\cos 180{}^\circ =-1 $ .
BETA
