Do the domains of odd and even functions have to be r?

Do the domains of odd and even functions have to be r?

Generally speaking, this is true, but it's not a dead and dead rule. It's not a bad thing to regard 1 / X as an odd function. It's just to note that there is no definition at 0. Of course, the domain of definition must be symmetrical about the origin, which is determined by the definition of odd and even functions

It is known that the function f (x) is an even function on the domain R. when x ≥ 0, f (x) = x / (1 + x). Find the analytic expression of the function f (x). Prove that the equation f (x) = 2 is the base
It is known that the function f (x) is an even function in the domain R. when x ≥ 0, f (x) = x / (1 + x). 1. Find the analytic expression of the function f (x). 2. Prove that the equation f (x) = 2 has a solution to the (1-x) power at (1,2)

1. Finding the analytic expression of function f (x)
x

Add appropriate operation symbols and brackets to the following formula to make the equation 0.5 () 0.5 () 0.5 () 0.5 () 0.5 = 0.5

（0.5-0.5）×0.5+0.5
The answer is not unique

Are all eigenvalues of real matrix real numbers
If not, what kind of matrix eigenvalues are real numbers? Do complex matrix eigenvalues have real numbers?

The eigenvalues of a real matrix are not always real numbers. Only the eigenvalues of a real symmetric matrix are guaranteed to be real numbers. The eigenvalues of a complex matrix may also have real numbers. For example, the eigenvalues of [1 I; - I 1] are 0 and 2, both of which are real numbers

What's the probability that the sum of four digits equals 24
8637, for example

There are 9999-999 = 9000 four digit numbers from 1000 to 9999
There are 405 of which the sum of the numbers is equal to 24
The probability that the sum of four digits equals 24 is 405 △ 9000 = 0.045

Let the rank of 4 * 5 matrix a be 3, the rank of 5 * 2 matrix B be 2, and ab = O. it is proved that if the vector B is the solution of the system of homogeneous equations AX = 0, then the system of non-homogeneous equations by = B must have a unique solution

With the discussion of block and rank proof. Economic mathematics team to help you answer. Please timely evaluation

The difference between a number minus 2 / 3 is equal to the sum of 1 / 3 and 1 / 2. What is the number? (list the equation for calculation)

Let this number be X
X-2/3=1/3+1/2
X-2/3=5/6
X=2/3+5/6
X=3/2

How many centimeters is six inches?

1 inch = 0.0254m
therefore
6in = 0.0254 * 6 = 0.1524m = 15.24cm

Xiaotu read a 192 page story book. On the first day, he read one eighth of the whole book, and on the second day, he read one sixth of it
(1) How many pages have you read in these two days?
(2) What page should I read on the third day?

(1) The first day read 192 / 8 = 24 pages; the second day read 192 / 6 = 32 pages; two days read a total of 24 + 32 = 56 pages
(2) The third day should start from page 57

Subtract the power of 4ab-3d from a person's polynomial to get the power of 2a-3ab to find the polynomial

Because a polynomial subtracts the power of 4ab-3d to get the power of 2a-3ab
So this polynomial is 2A & # 178; - 3AB + (4ab-3d & # 178;) = 2A & # 178; + ab-3d & # 178;