System.Power(Decimal, Decimal) Method

Version: Available or changed with runtime version 1.0.

Raises a number to a power. For example, you can use this method to square the number 2 to get the result of 4.

Syntax

NewNumber :=   System.Power(Number: Decimal, Power: Decimal)

Note

This method can be invoked without specifying the data type name.

Parameters

Number
 Type: Decimal
The number you want to raise exponentially. This number is the base in the exponential method.

Power
 Type: Decimal
The exponent in the exponential method.

Return Value

NewNumber
 Type: Decimal

Example 1

var
    Number1: Decimal;
    Power1: Decimal;
    Result1: Decimal;
    Text000: Label '%1 raised to the power of %2 = %3';
begin
    Number1 := 64;   
    Power1 := 0.5;  
    Result1 := Power(Number1, Power1);  
    Message(Text000, Number1, Power1, Result1);
end;

On a computer that has the regional format set to English (United States), the first message window displays the following:

64 raised to the power of 0.5 = 8

This example shows that raising a number to the power of 0.5 corresponds to the square root of the number.

Example 2

This example shows a typical use for the POWER method.

If a principal amount P is deposited at interest rate R and compounded annually, then at the end of N years, the accumulated amount (A) is:

A = P(1 + R)^N

For example, you put LCY 2800 into a bank account that pays 5 percent, which is compounded quarterly. To determine what the amount will be in eight years, you must consider:

N = 32 payment periods (8 years times 4 quarterly periods)

R = 0.0125 per period (5 percent divided by 4 quarterly periods)

The accumulated amount A is:

A = LCY 2800(1 + 0.0125)³² =LCY 2800(1.4881) = LCY 4166.77

If a principal amount P is deposited at the end of each year at interest rate R (in decimal notation) compounded annually, then at the end of N years, the accumulated amount is:

A = P[((1 + R)^N - 1)/R]

This is typically called an annuity.

For example, you have an annuity in which a payment of LCY 500 is made at the end of each year. The interest on this annuity is 4 percent, which is compounded annually. To determine what the annuity will be worth in 20 years, you must consider:

R = 0.04

N = 20

The amount of the annuity A will be:

A = LCY 500[((1 + 0.04)²⁰ - 1)/0.04 = LCY 14,889.04

var
    P: Decimal;
    R: Decimal;
    N: Decimal;
    A: Decimal;
    FormatString: Text;
    Text000: Label 'Principal $%1 at a 5 percent interest rate is compounded quarterly.\\';
    Text001: Label '(Rate = %2)\\';
    Text002: Label 'The amount after %3 years = $%4.';
    Text003: Label 'Principal $%1 is deposited at the end of each year at a 4 percent interest rate, compounded annually.\\';
    Text004: Label '(Rate = %2)\\';
    Text005: Label 'The amount after %3 years = $%4.';
begin    
    FormatString := '<Precision,2><Standard Format,1>';  
    // Example 1  
    P := 2800;  
    R := 0.0125;  
    N := 32;  
    A = P * (Power(1 + R, N));  
    Message(Text000 + Text001 + Text002, P, R, N, Format(A,0,FormatString);  
    // Example 2  
    P = 500;  
    R = 0.04;  
    N = 20;  
    A = P * ((Power(1 + R, N) - 1)/R);  
    Message(Text001, P, R, N, Format(A,0,FormatString));  
end;

On a computer that has the regional format set to English (United States), the first message window displays the following:

Principal $2,800 at a 5 percent interest rate is compounded quarterly.

(Rate = 0.0125)

The amount after 32 years = $4166.77.

The second message window displays the following:

Principal $500 is deposited at the end of each year at a 4 percent interest rate, compounded annually.

(Rate = 0.04)

The amount after 20 years = $14889.04.

See Also

System Data Type
Get Started with AL
Developing Extensions