[VA] Short & Sweet Math Challenge #24: "2019 Spring Special 5-tier"

[Albert Chan]

(03-31-2019 02:51 PM)Juan14 Wrote:  For the last challenge.
Let cin(x) = sin(x+A), we have:
sin(sin(sin(x+A)+A)+A) = sin(x) or
sin(sin(x+A)+A)+A = x
For a given value of x, we can solve the last equation for A (A is a function of x).

Nice try, but identity cin(cin(cin(x))) = sin(x) does not hold

Example, with above cin(x) definition, and x = 1.0

sin(1) ≈ 0.841471
cin(cin(cin(1))) ≈ cin(cin(0.906981)) ≈ cin(0.844196) ≈ 0.796542

Even worse if x=Pi/2

sin(Pi/2) = 1
cin(cin(cin(Pi/2))) ≈ cin(cin(0.835085)) ≈ cin(0.789340) ≈ 0.752222