Question

In a triangle ABC show that B square minus C square by a square sin 2A + c square minus A square by b square into B + a square minus b square by sin c square sin 2 C is equal to zero

Answer 1

hey!!

Nice question...

sin²A/2+sin²B+C/2=1

As you know that the sum of all angle of triangle is 180°

<A+<B+C=180°

B+C=180°-A

B+C/2=180/2-A/2 {if we dividing by 2 on both side }

sin²(B+C/2)=sin²(90°-A/2} {multiplying by sin²on both side,}

sin²(B+C)=cos²A/2 ........1)

now 1 substituting on given question

we get ..

sin²A/2+cos²A/2

=>1 ...like[ sin²A+cos²A=1]

hope it helps you