In a triangle ABC, `cos^2A+cos^2B+cos^2C=`

In triangle ABC, cos^2A + cos^2B - cos^2C = 1, then the triangle is necessarily

Statement I: If in a triangle ABC, sin ^(2) A+sin ^(2)B+sin ^(2)C=2, then one of the angles must be 90^(@). Statement II: In any triangle ABC cos 2A+ cos 2B+cos 2C=-1-4 cos A cos B cos C

Statement I: If in a triangle ABC, sin ^(2) A+sin ^(2)B+sin ^(2)C=2, then one of the angles must be 90^(@). Statement II: In any triangle ABC cos 2A+ cos 2B+cos 2C=-1-4 cos A cos B cos C

If in a triangle ABC, cos^(2)A + cos^(2)B + cos^(2)C =1 , then show that the triangle is right angled.

Prove that in triangle ABC,cos^(2)A+cos^(2)B-cos^(2)C=1-2sin A sin B cos C

Statement I If in a triangle ABC sin ^(2) A+sin ^(2)B+sin ^(2)C=2, then one of the angle must be 90^(@). Statement II In any triangles ABC cos 2A+ cos 2B+cos 2C=-1-4 cos A cos B cos C

Prove that in triangle ABC , cos^(2)A+cos^(2)B-cos^(2)C=1-2sinAsinBcosC .

Prove that in triangle ABC , cos^(2)A + cos^(2)B + cos^(2)C lt 3/4 .