https://docs.vultr.com/clang/s....tandard-library/math

inverse hyperbolic cosine The inverse hyperbolic cosine, written as arcosh(x) or acosh(x), is the inverse function of the hyperbolic cosine. It is defined for x ≥ 1 and can be calculated using the formula:

acosh
(
𝑥
)
=
ln
⁡
(
𝑥
+
𝑥
2
−
1
)
acosh(x)=ln(x+
x
2
−1
​
)
In C, you can use acosh() from math.h, and in Java, you can use Math.acosh()