This website contains age-restricted materials including nudity and explicit depictions of sexual activity.
By entering, you affirm that you are at least 18 years of age or the age of majority in the jurisdiction you are accessing the website from and you consent to viewing sexually explicit content.
I tried to figure it out myself back in high school but the best I came up with is X^2 -->2x because it just fucking does.
https://www.calculusmadeeasy.org/4.html