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恒等式

Word · Noun

identity (mathematics); equation that holds true for all values

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Meanings

1 sense · 4 examples
1.

noun

identity; an equation that is true for all values of its variables

formal

A fundamental concept in algebra and trigonometry. Often denoted with the symbol '≡' (identity sign) to distinguish from conditional equations.

Gōu勾
gǔ股
dìng定
lǐ理
a²
+a
b²²
=
c²+
shì
shìb
yòng²
yú
zhí=
jiǎo
sānc
jiǎo²
xíng
de是
héng适
děng用
shì于
 直
 角
 三
 角
 形
 的
 恒
 等
 式
 。

The Pythagorean theorem a² + b² = c² is an identity that holds for right triangles.

Lǎo老
shī师
ràng让
wǒ我
men们
zhèng证
míng明
zhè这
gè个
sān三
jiǎo角
héng恒
děng等
shì式
 :
sin²θs
+i
cos²θn
=²
1θ
 
 +
 
 c
 o
 s
 ²
 θ
 
 =
 
 1
 。

The teacher asked us to prove this trigonometric identity: sin²θ + cos²θ = 1.

Show 2 more examples
 (
xx
+
y+
²
=y
 )
x²²
+
2=
x
yx
+²
y²
shì+
yī
gè2
jīx
běny
de
dài+
shù
héngy
děng²
shì
 是
 一
 个
 基
 本
 的
 代
 数
 恒
 等
 式
 。

(x + y)² = x² + 2xy + y² is a basic algebraic identity.

Zài在
shù数
xué学
tuī推
dǎo导
zhōng中
 ,
jīng经
cháng常
lì利
yòng用
héng恒
děng等
shì式
jìn进
xíng行
huà化
jiǎn简
 。

In mathematical derivations, identities are often used for simplification.