Given any positive real number, an algorithm is designed to find the area of the circle with this number as radius

Given any positive real number, an algorithm is designed to find the area of the circle with this number as radius

The algorithm is as follows: Step 1: input a positive real number; step 2: calculate s = π R2; step 3: output s

If for all real numbers x, inequality
1. If the inequality (x ^ 4 + 2x ^ 2 + 4) / M (x ^ 2 + 2) ≥ 1 holds for all real numbers x, find the value range of M

1. If the inequality (x ^ 4 + 2x ^ 2 + 4) / M (x ^ 2 + 2) ≥ 1 holds for all real numbers x, find the value range of M
x^4+2x^2+4=(x^2+1)^2+3>0,x^2+2>0
So first confirm that M > 0
(x^4+2x^2+4)/m(x^2+2)≥ 1
(x^2+1)^2+3≥m(x^2+1)+m
(x ^ 2 + 1) ^ 2-m (x ^ 2 + 1) + 3-m ≥ 0, formula
(x^2+1 -m/2)^2 -(m^2)/4 +3-m≥0
For all real numbers x, the inequality holds
Then - (m ^ 2) / 4 + 3-m ≥ 0
m^2+4m-12≤0
(m+2)^2≤16
-6≤m≤2
To sum up, 0

If the opposite of a number is a non positive number, then the number must be ()
A. Negative B. positive C. 0 or positive D. 0

If the opposite number of a number is not positive, then the number must be 0 or positive, so choose C

If the opposite of a number is nonnegative, then the number must be negative

Let this number be X
Then - x ≥ 0
∴x≤0
The number must be non positive