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.
4. Skin rash or lesions. One of the most visible symptoms of lupus is a butterfly-shaped rash that appears over the bridge of the nose and on both cheeks. About 50 percent of people with lupus have this rash. It can occur suddenly or appear after exposure to sunlight.