ABC is a triangle in which AB = AC and D is any point on BC. Which of the following statements is/are correct ? I. AB^2 - AD^2 = CD \times BD II. BC^2 + BD^2 - DC^2 = 2BD \times BC Select the answer using the code given below :

Explanation

I. If E is midpoint of BC, AB^2 = AE^2+BE^2 and AD^2 = AE^2+DE^2. So AB^2-AD^2 = BE^2-DE^2 = (BE-DE)(BE+DE) = CD \times BD. II. Since DC = BC - BD, squaring both sides gives DC^2 = BC^2 + BD^2 - 2BC \times BD. Rearranging gives BC^2 + BD^2 - DC^2 = 2BD \times BC. Both are true.

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