[Solved] The first derivative of is . Testosterone Supplements: Products, often in the form of pills, injections, or gels, designed to increase testosterone levels in the body, used for medical reasons or to enhance physical performance or libido. Viagra: A medication used primarily in the treatment of erectile dysfunction, helping to increase blood flow to the penis to help a man get and keep an erection. Erectile Disorder: This refers to a type of sexual impairment where an individual cannot sustain or achieve penile erection during sexual engagement. Erotic Plasticity: Erotic plasticity refers to the degree to which an individual's sex drive can be changed by societal, situational, and cultural influences.