Math.Max() / Math.Min() / Math.Pow() / Math.Sqrt()

using System;

// Returns the larger of val1 and val2.
Math.Max(T val1, T val2)

// Returns the smaller of val1 and val2.
Math.Min(T val1, T val2)

// Returns x raised to the power y. The return type is double.
Math.Pow(double x, double y)

// Returns the square root of d. The return type is double.
Math.Sqrt(double d)

// Returns the natural logarithm of x.
Math.Log(double x)

// Returns the logarithm of x in the specified base newBase.
Math.Log(double x, double newBase)

using System;

// Math.Max() — Returns the larger of two values.
Console.WriteLine(Math.Max(10, 20));    // 20
Console.WriteLine(Math.Max(-5, -3));    // -3
Console.WriteLine(Math.Max(3.7, 3.2)); // 3.7

// Math.Min() — Returns the smaller of two values.
Console.WriteLine(Math.Min(10, 20));    // 10
Console.WriteLine(Math.Min(-5, -3));    // -5

// Math.Pow() — Calculates a power.
Console.WriteLine(Math.Pow(2, 10));  // 1024 (2 to the power of 10)
Console.WriteLine(Math.Pow(3, 3));   // 27 (3 to the power of 3)
Console.WriteLine(Math.Pow(9, 0.5)); // 3 (9 to the power of 0.5 = square root)

// Math.Sqrt() — Calculates a square root.
Console.WriteLine(Math.Sqrt(16));   // 4
Console.WriteLine(Math.Sqrt(2));    // 1.4142135623730951
Console.WriteLine(Math.Sqrt(-1));   // NaN (square root of a negative number is not a real number)

// Math.Log() — Calculates a logarithm.
Console.WriteLine(Math.Log(Math.E));     // 1 (natural log: log_e(e) = 1)
Console.WriteLine(Math.Log10(1000));     // 3 (common log: log_10(1000) = 3)
Console.WriteLine(Math.Log(8, 2));       // 3 (log_2(8) = 3)

// Practical example: compound interest (principal × (1 + rate)^years)
double principal = 100000;
double rate = 0.03;
int years = 10;
double futureValue = principal * Math.Pow(1 + rate, years);
Console.WriteLine($"{years} years later: {futureValue:F0} yen");

The return value of Math.Pow() and Math.Sqrt() is always of type double. An explicit cast is required to assign the result to an integer variable. Note that passing a negative value to Math.Sqrt() returns NaN (Not a Number) rather than throwing an exception.

Math.Max() and Math.Min() can only compare two values at a time. To find the maximum or minimum value of an entire array or list, use LINQ's Max() / Min(). For absolute values and rounding, see Math.Abs() / Round() / Ceiling() / Floor().