7-dehydrocholesterol (sometimes known as provitamin D3) is a chemical that, in the presence of ultraviolet light, is converted by the body to previtamin D3 which is then isomerized into Vitamin D3.
... {b^2-4ac}}{2a}
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The term b2 – 4ac is called the discriminant of the quadratic equation, because it discriminates between three qualitatively ...