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

Similar Questions

Explore conceptually related problems

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

cos A + cos B + cos C = 1 + 4sin ((A) / (2)) sin ((B) / (2)) sin ((C) / (2))

If A + B + C =pi , prove that : cos 2A + cos 2B -cos 2C= 1-4sin A sin B cos C .

If A+B+C=180^0 , prove that : cos^2 (A/2) + cos^2 (B/2) - cos^2 (C/2) = 2cos (A/2) cos (B/2) sin (C/2)

If A + B + C =pi , prove that : cos 2A + cos 2B + cos 2C = -1-4 cos A cos B cos C .

If A + B + C =180^@ , prove that : cos^2 A+ cos^2 B-cos^2 C= 1-2 sin A sin B cos C .

If A + B + C = (pi)/(2) , prove that cos 2A + cos 2B + cos 2C = 1 + 4 sin A sin B cos C

If A + B + C = pi , prove that cos A + cos B + cos C= 1 + 4 sin(A/2) sin(B/2) sin(C/2)

If A + B + C =pi , prove that : cos 2A - cos 2B- cos 2C= -1+4 cos A sinB sin C .

If A + B + C =180^@ , prove that : cos^2 A+ cos^2 B+cos^2 C=1-2 cos A cos B cosC .