Introduce inverse hyperbolic functions

#KT-4900

Improve accuracy of JS polyfills of hyperbolic functions and expm1/log1p

libraries/stdlib/common/src/kotlin/MathH.kt

@@ -140,6 +140,49 @@ public expect fun cosh(a: Double): Double
 @SinceKotlin("1.2")
 public expect fun tanh(a: Double): Double
 
+/**
+ * Computes the inverse hyperbolic sine of the value [a].
+ *
+ * The returned value is `x` such that `sinh(x) == a`.
+ *
+ * Special cases:
+ *
+ *     - `asinh(NaN)` is `NaN`
+ *     - `asinh(+Inf)` is `+Inf`
+ *     - `asinh(-Inf)` is `-Inf`
+ */
+@SinceKotlin("1.2")
+public expect fun asinh(a: Double): Double
+
+/**
+ * Computes the inverse hyperbolic cosine of the value [a].
+ *
+ * The returned value is positive `x` such that `cosh(x) == a`.
+ *
+ * Special cases:
+ *
+ *     - `acosh(NaN)` is `NaN`
+ *     - `acosh(x)` is `NaN` when `x < 1`
+ *     - `acosh(+Inf)` is `+Inf`
+ */
+@SinceKotlin("1.2")
+public expect fun acosh(a: Double): Double
+
+/**
+ * Computes the inverse hyperbolic tangent of the value [a].
+ *
+ * The returned value is `x` such that `tanh(x) == a`.
+ *
+ * Special cases:
+ *
+ *     - `tanh(NaN)` is `NaN`
+ *     - `tanh(x)` is `NaN` when `x > 1` or `x < -1`
+ *     - `tanh(1.0)` is `+Inf`
+ *     - `tanh(-1.0)` is `-Inf`
+ */
+@SinceKotlin("1.2")
+public expect fun atanh(a: Double): Double
+
 /**
  * Computes `sqrt(x^2 + y^2)` without intermediate overflow or underflow.
  *
@@ -527,6 +570,49 @@ public expect fun cosh(a: Float): Float
 @SinceKotlin("1.2")
 public expect fun tanh(a: Float): Float
 
+/**
+ * Computes the inverse hyperbolic sine of the value [a].
+ *
+ * The returned value is `x` such that `sinh(x) == a`.
+ *
+ * Special cases:
+ *
+ *     - `asinh(NaN)` is `NaN`
+ *     - `asinh(+Inf)` is `+Inf`
+ *     - `asinh(-Inf)` is `-Inf`
+ */
+@SinceKotlin("1.2")
+public expect fun asinh(a: Float): Float
+
+/**
+ * Computes the inverse hyperbolic cosine of the value [a].
+ *
+ * The returned value is positive `x` such that `cosh(x) == a`.
+ *
+ * Special cases:
+ *
+ *     - `acosh(NaN)` is `NaN`
+ *     - `acosh(x)` is `NaN` when `x < 1`
+ *     - `acosh(+Inf)` is `+Inf`
+ */
+@SinceKotlin("1.2")
+public expect fun acosh(a: Float): Float
+
+/**
+ * Computes the inverse hyperbolic tangent of the value [a].
+ *
+ * The returned value is `x` such that `tanh(x) == a`.
+ *
+ * Special cases:
+ *
+ *     - `tanh(NaN)` is `NaN`
+ *     - `tanh(x)` is `NaN` when `x > 1` or `x < -1`
+ *     - `tanh(1.0)` is `+Inf`
+ *     - `tanh(-1.0)` is `-Inf`
+ */
+@SinceKotlin("1.2")
+public expect fun atanh(a: Float): Float
+
 /**
  * Computes `sqrt(x^2 + y^2)` without intermediate overflow or underflow.
  *