The plus–minus sign or plus-or-minus sign (±) and the complementary minus-or-plus sign (∓) are symbols with broadly similar multiple meanings. In mathematics, the ± sign generally indicates a choice of exactly two possible values, one of which is obtained through addition and the other through subtraction.

Representing the range of error or uncertainty: In measurements, scientific notation, or statistical data, the plus-minus symbol is used to indicate the range of error or uncertainty associated with a value. This is often seen in the context of confidence intervals or error margins. For example:

If the $\pm$ sign is confusing you, get rid of it. If you have $$15 = \pm(a+x)$$ you can turn that into two equations: $$15 = a+x\\15 = -(a+x)$$ and then deal with the two equations separately, one at a time. That is exactly the meaning of the $\pm$ sign.

2016年6月3日 · What is the meaning of the $\pm$ symbol in relation to this expression? For example, the perceived area of a circle probably grows somewhat more slowly than actual (physical, measured) area: $$ \text{the reported perceived area} = (\text{actual area})^x, \text{where }x= \color{red}{\underline{\color{black}{.8 \pm .3}}}, $$ a discouraging result.

If both "$\pm$" and "$\mp$" are used, it often means that all the terms with "$\pm$" have the same sign and all the with "$\mp$" have the opposite sign. For example, the expression "$a\pm b \mp c \pm d \mp e$" would mean that $b$ and $d$ would have the same sign (either "+" or "-"), and $c$ and $e$ would have the opposite sign.

Arguably the most common appearance of the plus/minus sign in mathematics is to denote the two solutions of the general equation of degree two: 1. Insert a plus minus sign in LaTeX. In general, the plus-minus symbol is generated in LaTeX with the \pm command inside math mode. For example, the previous equation was produced with: 2.

PM = Post meridiem: After noon. 意思是在中午后. meridiem /mə'ridi:əm/ n.正午. Ante meridiem is commonly denoted as AM, am, a.m., or A.M.; post meridiem is usually abbreviated PM, pm, p.m., or P.M. Ante meridiem通常会写成AM, am, a.m., 或者是A.M. post meridiem会缩写为PM, pm, p.m., …

“am”和“pm”分别表示什么时间？时间am的全称是 ante meridiem(before noon)， 上午 （0：00-12：00）。时间pm的全称是post meridiem (=afternoon) ，下午（12：01-24：00)。时间单位其指时辰，古时一天分12个时辰

There's a reason why the \pm symbol sits on the baseline, rather than be centered to the axis, which makes it difficult to split the two parts. In any case, use "plus or minus" very sparingly other than for denoting error intervals, as it's generally very ambiguous.

PM表示下午，上午是AM. PM，拉丁语post meridiem的缩写，意为午后，用于十二小时制。所谓“午后”，即每天的12：00：00～23：59：59时段。 与PM相对，上午AM，拉丁语为：ante meridiem，意为“中午之前”。 扩展资料： 常用英文缩写：