ABC is an isosceles triangle in which AB=AC and D is a point on BC . Prove that ABsq-ADsq=BD.CD

ABC is an isosceles triangle in which AB=AC and D is a point on BC . P

1.	ABC is an isosceles triangle in which AB=AC and D is a point on BC . Prove that ABsq-ADsq=BD.CD
Answer» I prove it.