Cannot figure it out why it is like that considering x and k positive... Please anyone can explain it to me? Thx I mean why it is like that and not: cos(x/k)-1 ? Sent from my Redmi Note 4X using Tapatalk
Follow Math Help Forum on Facebook and Google+
$-1 \le \cos(x/k) \le 1 \implies \cos(x/k)-1 \le 0$ and $1-\cos(x/k) \ge 0$