In a triangle ABC, using vector prove that `c^(2)=a^(2)+b^(2)-2abcosC`

In a triangle ABC, prove that (b + c)/(a) le cosec.(A)/(2)

If A D is the median of A B C , using vectors, prove that A B^2+A C^2=2(A D^2+C D^2)dot

In acute angled triangle ABC prove that tan ^(2)A+tan^(2)B+tan^(2)Cge9 .

For any triangle ABC, prove that a(bcosC-ccosB)=b^2-c^2

In any triangle ABC prove that cot(A/2)+cot(B/2)+cot(C/2)=cot(A/2)cot(B/2)cot(C/2)

For any triangle ABC, prove that (b^2-c^2)/(a^2)sin2A+(c^2-a^2)/(b^2)sin2B+(a^2-b^2)/(c^2)sin2C=0

For any triangle ABC, prove that sin(B-C)/2=(b-c) /a ( cosA/2)

In a triangle ABC if 2Delta^(2)=(a^(2)b^(2)c^(2))/(a^(2)+b^(2)+c^(2)) , then it is

In a triangle ABC, prove that (cot(A/2)+cot(B/2)+cot(C/2))/(cotA+cotB+cot(C))=((a+b+c)^2)/(a^2+b^2+c^2)

In any triangle A B C , prove that: Delta=(b^2+c^2-a^2)/(4cotA) .