In a `DeltaABC" if " a:b:c=7:8:9` then show that `cosA:cosB:cosC=14:11:6`

In Delta ABC if a: b: c = 7 : 8: 9 , then cos A : cos B : cos C =

In a /_\ABC , if a:b:c = 7:8:9 , then find cosA:cosB:cosC .

In a DeltaABC, " if "a:b:c=4:5:6 , then the ratio of the radius of the circumcircle to the radius of the incircle is

In a DeltaABC" if " a =13,b=14,c=15 " then show that " R =(65)/(8),r=4,r_(1)=(21)/(2),r_(2)=12,r_(3)=14

In DeltaABC, c (a cosB-b cosA)=

If A+B+C=0 then show that 1+cosA+cosB+cosC=4"cos"A/2"cos"B/2"cos"C/2

In Delta ABC, if cot""A/2:cot""B/2:cot""C/2=3:7:9 , then a:b:c=

If A+B+C = 180^(@) , then show that cos2B+cos2B+cos2C = -4 cosA.cosB.cosC-1 .

If A,B,C are angles in a triangle , then prove that cosA+cosB+cosC=1+4sin. (A)/(2)sin. (B)/(2) sin. (C)/(2)

IF A,B,C are angles in the triangle, then prove that cosA+cosB-cosC=-1+4cos""A/2.cos""B/2.sin""C/2