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.
The most common symptoms of lupus (which are the same for men and women) are: 1  Extreme fatigue (tiredness) 2  Headaches. 3  Painful or swollen joints. 4  Fever. 5  Anemia (low numbers of red blood cells or hemoglobin, or low total blood volume) 6  Swelling (edema) in feet, legs, hands, and/or around eyes. 7  Pain in chest on deep breathing (pleurisy)