The Quotient Rule says that the derivative of a quotient is the denominator times the derivative of the numerator minus the numerator times the derivative of the denominator, all divided by the square of the denominator,

The derivative of the difference of functions is equal to the difference of the derivatives of the functions.

The derivative of the sum of functions is the same as the sum of the derivatives of the functions.

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\begin{array}{|c|c|} \hline

2&2 \\ \hline

2&2 \\ \hline

2&2 \\ \hline

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Heron's formula gives the area of a triangle when the lengths of all three sides are known. Given the lengths of the three sides of a triangle, a, b, c, the area of the triangle can be determined as

A = \sqrt{s(s-a)(s-b)(s-c)}

where s = \dfrac{a+b+c}{2} , semi-perimeter of the triangle.

The formula can be transformed to the following interesting forms.