graphing calculator

[joeyjon]

why does my graphing calculator say a negative number squared is negative?


says -1 squared = -1

Am I in the wrong mode?

 

[pka]

why does my graphing calculator say a negative number squared is negative? Says -1 squared = -1

Try $\displaystyle (-1)^2$

You see $\displaystyle -x^2$ is the negative of $\displaystyle x^2$

So $\displaystyle -1^2=-1$ any place.

 

[joeyjon]

Well that makes sense. Thanks.

 

[Deleted member 4993]

Try $\displaystyle (-1)^2$

You see $\displaystyle -x^2$ is the negative of $\displaystyle x^2$

So $\displaystyle -1^2=-1$ any place.

Except in MS-Excel

where, in a cell:

if you type =-2^2 the display will be 4

if you type =-2^2 + 8 the display will be 12

if you type = 8 - 2^2 the display will be 4

 

[pka]

Except in MS-Excel
where, in a cell:
if you type =-2^2 the display will be 4
if you type =-2^2 + 8 the display will be 12
if you type = 8 - 2^2 the display will be 4

Well that is Excel, what else do you expect?

 

[tkhunny]

It's not just Excel. In many environments, the Unary Minus (-2) is very high precedence, whereas simple Subtraction (8-2) is several precedence levels lower. In one language (APL), to help avoid confusion, there is a different symbol for Unary Minus.

Here's a decent article: http://unlearningmath.com/2009/05/26/notes-on-operations-unary-minus/

IBM built in the ability to define precedence, realizing that a different token would be necessary: http://publib.boulder.ibm.com/infoc...p?topic=/com.ibm.zvm.v54.dmsp4/hcsp4b1087.htm