If cosA + cosB `=4sin^(2)(C/2)`, then

In triangleABC , If cosA+cosB+cosC=(3)/(2) , then the triangle is

If A+B+C=pi , prove that : cosA + cosB-cosC=4cos(A/2) cos(B/2) sin(C/2) -1

If cosA+cosB=m and sinA+sinB=n then sin(A+B)=

If cosA+cos^(2)A=1 , then prove that sin^(2)A+sin^(4)A=1 .

Using properties of determinant. Prove that | [sinA, cosA, sinA + cosB], [sinB, cosA, sinB + cosB], [sinC, cosA, sinC + cosB] | = 0

If in a triangle A B C ,(1+cosA)/a+(1+cosB)/b+(1_(cosC))/c =(k^2(1+cosA)(1+cosB)(1+cosC)/(a b c) , then k is equal to 1/(2sqrt(2)R) (b) 2R (c) 1/R (d) none of these

If cos(A - B) = (3)/(5) and tanA tanB = 2, then the value of cosA cosB is _____

If A+B+C+D=2pi , show that : cosA-cosB+cosC-cosD=4sin( (A+B)/(2)) sin( (A+D)/(2)) cos( (A+C)/(2)) .