专业英语中的常用符号和数学式表达
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专业英语中的常用符号和数学式的表达
1/2
a
half,
one
half
1/3
a
third,
one
third
2/3
two
thirds
1/4
a
quarter,
one
quarter,
a
fourth,
one
fourth
1/100
a(one)
hundredth
1/1000
a(one)
thousandth
113/324
one
hundred
and
thirteen
over
three
hundred
twenty
four
4
2
3
four
and
two
thirds
0.25
zero (0,
naught)
point
two
five
+
plus ,
positive
_
minus,
negative
±
plus
or
minus
×
multiplied
by ,
times
÷
divided
by
=
be
equal
to,
equals
≈
be
approximately
equal
to,
approximately
equals
()
round
brackets;
parentheses
【】
square
(angular)
brackets
{}
braces
≢
less
than
or
equal
to
and
1
≣
more
than
or
equal
to
∞
infinity
∵
because
∴
therefore
maps
into
X+y
x
plus
y
(a+b)
bracket
a
plus
b
bracket
closed
A=b
a
equals
b;
a
is
equal
to
b;
A
≠
b
a
is
not
equal
to
b
A
±
b
a
plus
or
minus
b
A
≈
b
a
is
approximately
equal
to b
A
＞
b
a
is
greater
than
b
A
＞＞
b
a
is
much[far]
greater
than
b
A
a
is
less
than
b
A<
a
is
much
less
than
b
A
⊥
b
a
is
perpendicular
to b
X
∞
x
approaches
infinity
A
≡
b
a is
identically
equal
to
b;
a
is
∟
a
angle
a
A
～
b
the
difference
between
a
and
b
A
∠
b
a
is
parallel
to
b
A
∝
b
a
varies
directly
as
b
a
is
b
of
identity
to
b
2
x
2
:
x
square;
x
squared;
the
square
of
x;
the
second
power
of
x;
x
to
second
power
x
3
:
x
cube;
x
cubed;
the
cube
of
x;
the
third
power
of
x;
x
to the
third
power
x
3
the
square
root
of
x
the
cube
root
of
x
x
%
percent
2%
two
percent
‰
per
mill
5
‰
five
per
mill
log
n
x
log
10
x
log
e
x
log
x
to
the
base
n
log
x
to
the
base
10;
common
logarithm
ln
x
,
log
x
to
the
base
e;
natural
logarithm;
napierian
logarithm
e
x
,
exp(
x
)
x
n
x
1
n
exponential
function
of
x;e
to the
power
x
the
nth
power
of
x;
x
to
the
power
n
n
或
x
the
nth
root
of
x;
x
to
the
power
one
over
n
Sin
sine
Cos
cosine
Tg,
tan
tangent
Ctg,
cot
cotangent
3
Sc,
sec
secont
Csc,
coses
cosecant
sin
1
,
arcsin
:
arc
sine
cos
1
,
arcos
:
arc
cosine
Sinh
:
the
hyperbolic
sine
Cosh:
the
hyperbolic
cosine
∑
:
the
summation
of
n
x
i
:
the
summation
of
x
sub
I,
where
I
goes
from
i
1
to
n
∏
:
the
product
of
x
:
the
absolute
value
of
x
x
:
the
mean
value
of
x;
x
bar
b
:
b
prime
b
:
b
double
prime;
b second
prime
b
:
b
triple
prime
f
x
:
function
f
of
x
∡
；
finite
difference
or
increment
x
:
the
increment
of
x
dx
:
dee
x;
dee
of
x;
differential
x
dy
dx
:
the
differential
coefficient
of
y
with
respect
to
the
first
derivative
of
y
with
respect
of
x
1
x;
4