In a ΔABC(a+b+c)(b+c−a)(c+a−b)(a+b−c)4b2c2equals
cos2 A
cos2 B
sin2 A
sin2 B
We know that,2s=a+b+c∴(a+b+c)(b+c−a)(c+a−b)(a+b−c)4b2c2=2s(2s−2a)(2s−2b)(2s−2c)4b2c2=4s(s−a)bc×(s−b)(s−c)bc=4cos2A2×sin2A2=sin2A
In any ΔABC, (a+b+c)(b+c−a)(c+a−b)(a+b−c)4b2c2 is equal to