negative number raised to even power

[Gerald H]

(05-06-2015 07:56 PM)Wes Loewer Wrote:  

(04-26-2015 07:20 AM)Thomas Radtke Wrote:  MS Excel.

Check out https://support.microsoft.com/en-us/kb/kbview/132686 where Microsoft says "This order of precedence may mean that a formula returns a positive value when you expect it to return a negative value."

Here's a table showing how various calculators/software handle the following order of operations issues:
-2^2 = (a) -4 (b) 4
2^3^2 = (a) 512 (b) 64
1/2pi = (a) 1.57 (b) 0.159

Calculators
aaa: HP Prime Algebraic Entry
aab: HP Prime Textbook Entry/50g EQW (but 1/2pi is shown as stacked fraction and is not ambiguous)
aaa: HP 50g Alg mode
abb: Casio fx-9960G
abb: TI 81/82/85/86
aba: TI 73/83/83+/84+(Classic Mode)
aaa: TI 84+(MathPrint Mode)/89/Nspire

Software
bb-: Excel
bb-: OpenOffice
ba-: Google Docs Sheet
ba-: Gnumeric (formula bar shows "(-2)^2" and "2^(3^2)")
ab-: Corel Quattro Pro
ba-: Corel WordPerfect Table
aa-: Maxima
aaa: Wolfram Alpha
aaa: GeoGebra

Legacy Software
bb-: VisiCalc
??-: Lotus 123 (can someone test this)
ab-: Lotus Improv (anybody remember this spreadsheet?)

This is certainly not a complete list, just what I had handy to test. All the calculators I tested agreed that -2^2=-4, but the other issues were mixed. The more recent HP and TI calculators agree with -4, 512, and 1.57.

Lotus 123, 2.4: aba