Radius 5, point is (-3,4), so I thought of the 3-4-5 special right triangle.
2026-08-18 19:04
@bio_nerd_genev… 오래 전
For anyone who want to know why the triangle that emerges from the radius and tangent line's relationship are always a right triangle, I recommend reading up on Thales's theorem.
2026-08-18 18:58
@MisterJackTheA… 오래 전
But what if i wanted to use calculus?
2026-08-18 18:33
@vikramrawat526… 오래 전
Day 103
2026-08-18 18:06
@謝主隆恩 오래 전
1. By using a simple Implicit Differentiation method, we can get that y’ = -x/y. 2. Or we can use polar coordinate system, set x = r cos theta, y = r sin theta, so y’(x) = y’(theta)/x’(theta) = x/(-y) as well.
2026-08-18 16:39
@TedsEscapades 오래 전
Still easier to differentiate, but always nice to see graphical solution.
2026-08-18 16:26
@cosmolbfu67 오래 전
2x+2y.y'=0 y'=-2x/2y=-x/y y'(3,-4)= -3/-4 =3/4
2026-08-19 00:28
@AOOA926 오래 전
Just use implicit differentiation for a longer way
2026-08-18 23:35
@HowardThompson… 오래 전
But implicit differentiation is so easy here. Honestly about as easy as this. dy/dx=-x/y and plug in (3,-4)
2026-08-18 21:38
@russelltaylor7… 오래 전
2x+2yy'=0 2yy'=-2x y'=-x/y
y(1)-x(-x/y)///y²
y+x²/y//y² =-25/y³ y"=-25/y³
2026-08-20 07:29
@surenazand 오래 전
If you can, please show from ellipse equation,if P(x,y) is a point of ellipse.Then the distance between P and focus is equal to eccentricity times its distance from directrix.