If `A+B+C=90^(@) " then " cos^(2) A + cos^(2) B + cos^(2) C =`

If A+B+C=180^@ " then " cos^(@) A + cos^(2)B + cos^(2)C=

If A+ B + C = pi, then cos^(2) A + cos ^(2) B + cos ^(2) C is equal to : A) 1 - cos A cos B cos C B) 1 - 2 cos A cos B cos C C) 2 cos A cos B cos C D) 1 + cos A cos B cos C

If A+B+C=90^(@) " then " ( cos 2A + cos 2 B+ cos 2C-1)/( sin A sin B sin C )=

If A+B+C=0 , then prove that cos ^(2)A+ cos ^(2) B + cos ^(2) C =1+2 cos A cos B cos C

If A+B+C=180^(@) then prove that cos^(2)A+cos^(2)B-cos^(2)C=1-2sin A sin B cos C

If : A+B+C=pi, "then" : 1-cos^(2) A-cos^(2)B-cos^(2)C= A) 2 cos A * cos B * cos C B) 2 sin A * cos B * cos C C) 2 cos A * sin B * cos C D) 2 cos A * cos B * sin C