• sarchar
    link
    fedilink
    English
    arrow-up
    5
    ·
    2 months ago

    It’s weird to picture, but every point on the circle has a tangent vector which is, by definition, at a right angle to the radius vector, which is what the sides of that larger pie piece both are.

    You have to think of the infinitesimally small point where the two meet.