What do 26 English letters stand for in mathematics

What do 26 English letters stand for in mathematics

This is not necessarily, I said a few commonly used it. Pay attention to the case oh
C: Girth
d: The diameter of a circle
h: High
l: Length
O: The center and origin of a circle
r: Radius of a circle
S: Area
5: Volume

Who knows the special meaning of 26 English letters

According to the rule that the solution of X + 1 / x = a + 1 / A is x = a or x = 1 / A, the fractional equation x + 1 / (x-3) = 8 and 1 / 5 is solved

It is known that the original equation is
x+1/(x-3)=8+1/(8-3)
From the solution of X + 1 / x = a + 1 / A to x = a or x = 1 / A, let y = x-3, have
x+1/y=8+1/5
X = 8 or 1 / y = 1 / 5
y=5=x-3
So the solution of the original equation is
X = 8 or x = 1 / 8

What is 12 out of 24 reduction

12/24=1/2

If the quadratic function is known to pass through points (0,3), (4,6), and the axis of symmetry is a straight line x = 5 / 3, the analytical formula of parabola is obtained

Let y = a (X-5 / 3) ^ 2 + B = 0
Substituting (0,3), (4,6)
A = 9 / 8, B = - 1 / 8
So y = 9 / 8 (X-5 / 3) ^ 2-1 / 8

What is the quotient of 10.2 minus 2.5 divided by the product of 0.3 and 2?

It's 12 plus five

Let u = R, a = {x | a ≤ x ≤ 2A + 3}, B = {x | - 1 ≤ x ≤ 5}, if a ∩ B = empty set, find the value range of A

It is known that B = {x | X5}
So a = {x | a ≤ x ≤ 2A + 3}
So a ≥ - 1 and 2A + 3 ≤ 5
So - 1 ≤ a ≤ 1

Xiaowan's mobile phone received the following message: "think of a number, add 52.8 to it, multiply by 5, subtract 3.9343, divide by 0.5, and finally subtract ten times of the number in mind. The answer is very romantic!" According to the above instructions, let the number in Xiaowan's mind be x, and find out the romantic number

According to the meaning of the title, we get 10.5 [5 (x + 52.8) - 3.943] - 10x, = 2 (5x + 264-3.943) - 10x, = 520.1314

The difference between the polynomial 4k2 + 7K and the polynomial-k2 + 3K-1 is ()
A. 3k2+10k-1B. 5k2+4k+1C. 3k2+4k+1D. -5k2-4k-1

According to the meaning of the title: (4k2 + 7K) - (- K2 + 3K-1) = 4k2 + 7K + k2-3k + 1 = 5k2 + 4K + 1

It is known that sina = 1 / 3360 degree

sina=sin(2*a/2)=2sina/2cosa/2
Let (Sina / 2 + cosa / 2) be squared,
=sin^2a/2+2sina/2cosa/2+cos^2a/2
=sin^2a/2+cos^2a/2+sina
=1+1/3
=4/3
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