Product Rule. If the two functions f(x) and g(x) are differentiable (i.e. the derivative exist) then the product is differentiable and, The proof of the Product Rule is shown in the Proof of Various Derivative Formulas section of the Extras chapter.
Inflammation is the most common reason for muscle pain and aches. Any time that major inflammation exists (strep throat, hepatitis, cancer, lupus, acute heart attack, etc.), signs and symptoms often include fevers, sweats, chills, fatigue, weight loss, and various muscle aches, pains and weakness.
About 1 in 10 people with discoid lupus eventually develop systemic lupus, and about 3 in 10 people with systemic lupus have discoid lupus rashes. Drug-induced lupus can develop with certain medicines. In a very small number of people, certain prescription medicines lead to the development of S.L.E. symptoms.