Home
Class 12
MATHS
cos A + cos ( 120 ^@+A ) + cos ( 120^@ ...

`cos A + cos ( 120 ^@+A ) + cos ( 120^@ -A )` is

A

0

B

1

C

`3/2`

D

`2/3`

Text Solution

Verified by Experts

The correct Answer is:
A
Promotional Banner

Topper's Solved these Questions

  • TRIGONOMETRIC FUNCTIONS

    NEW JOYTHI PUBLICATION|Exercise QUESTIONS FROM COMPETITIVE EXAMS|134 Videos

  • TRIGONOMETRIC FUNCTIONS

    NEW JOYTHI PUBLICATION|Exercise QUESTIONS FROM COMPETITIVE EXAMS|134 Videos

  • THREE DIMENSIONAL GEOMETRY

    NEW JOYTHI PUBLICATION|Exercise Objective|36 Videos

  • VECTOR ALGEBRA

    NEW JOYTHI PUBLICATION|Exercise CONTINUOUS EVALUATION|2 Videos

Similar Questions

Explore conceptually related problems

cos ^3 A + cos^3 (120 +A ) + cos ^3 (120 - A) is

cos 4x = cos 2x

Prove that cos (30^(@) -A ) cos (30^(@) + A ) + cos (45^(@) - A) cos (45^(@) + A) = cos 2A + (1)/(4) .

Prove that (i) sin A+sin (120^(@)+A)+sin(240^(@)+A)=0 (ii) cos A+cos (120^(@)+A)+cos (120^(@)-A)=0

Show that (cos 8 A cos 5A - cos 12 A cos 9A )/( sin 8 A cos 5A + cos 12 A sin 9A ) = tan 4A

cos 1^@ + cos 2^@ + cos 3^@ + cos 4^@ + ……….. Cos 179^@ = …………………….. .

If A + B + C = 180^(@) , prove that cos A + cos B - cos C = -1 + 4 cos (A)/(2) cos"" (B)/(2) sin"" (C )/(2)

Prove that cos (A + B) cos C - cos (B + C) cos A = sin B sin (C - A)

Prove that cos (A + B) cos (A - B) = cos^(2) A - sin^(2) B = cos^(2) B- sin^(2) A

If in a triangle ABC, (1 + cos A)/(a) + (1 + cos B)/(b) + (1+ cos C)/(c) = (k^(2) (1 + cos A) (1 + cos B) (1 + cos C))/(abc) , then k is equal to