Question

if a,b and c are the lengths of three sides of a triangle,than- (1)(a+b)>c ,(2)(a-b)>c ,(3)(a+b)=c ,(4)(a-b)=c​

Answer 1

(a+b+c)(b+c−a)=k.bc

(b+c)

2

−a

2

=k.bc

b

2

+c

2

+2bc−a

2

=kbc

2bc+2bccosA=kbc

k=4cos

2

2

A

⟹0<k<4