jan 1, 600 - Bramagupta: Wrote book with ARITHMETIC RULES and had some MISTAKES Wrote formula for area of cyclic quadrilateral (quadrilaterals in circles): - where S = perimeter = a+b+c+d - A = sqrt((s-a)(s-b)(s-c)(s-d)) If d = 0 is area of triangle --> A = sqrt((s-a)(s-b)(s-c)) First to write quadratic formula
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Date:
jan 1, 600
Now
~ 1426 years ago