On functions 1. It is known that f (x) is an increasing function on (- ∞, + ∞). If a + B ≤ 0, then f (x) is an increasing function A.f (a)+f (b) ≤－f (a) －f (b) B.f (a)+f (b)≥－f (a) －f (b) C.f (a)+f (b) ≤f (－a) ＋f (－b) D.f (a)+f (b)≥f (－a) ＋f (－b) 2. If f (1 / x) = x / (1-x2), then f (x) =? Note: (1-x2) is a whole, and its 2 represents the square of X

1.C.
Because a + B ≤ 0, count a

RELATED INFORMATIONS

1. Ask for a math problem about function F (x) = ax ^ 2 + (b-2) x + 3 is the even function defined on [2a-1,2-a]. Find the range of function
2. Exponential function f (x) = 2 ^ x + 1 / (2 ^ | x |) = 2, then x =?
3. A mathematical problem of function Given that f (x) is an odd function, G (x) is an even function, and f (- 1) + G (1) = 2, f (1) + G (- 1) = 4, then G (1) =?
4. Beijing Olympic Games + Olympic Games + Olympic Games = 2008 what are the numbers of Beijing, Beijing, Olympic Games and Olympic Games
5. Quick calculation formula of profit rate I'd like to ask my brothers, sisters, brothers and sisters. For example, I sold 5000 yuan of products, and the unit price profit of each product is 60%. What's the cost and profit of 5000 yuan? How can I get a formula? If 5000 * 60% (0.6) = 3000 yuan, is the profit? And 2000 yuan is the cost? So I think my actual cost is close to 3000 yuan, but the profit is less than 2000 yuan. If my unit cost is 1.2 yuan, then I want 300 yuan for 5000 yuan sales, How do I get a formula? How many times 1? Please give it to a specific company. Please bring a formula with numbers. I'm not good at math. I'm going to study accounting today
6. Known circle C: (x-3) ^ 2 + y ^ 2 = 100. A (- 3,0) Following title: P is any point of circle C, the vertical bisector l of line PA intersects PC at Q point, and the trajectory equation of Q point is obtained Make a straight line AB through the point P (1,1), which respectively intersects the positive half axis of X axis and the positive half axis of Y axis at two points a (a, 0). B (0, b). When a is the value, the area of triangle AOB is the smallest, and what is the minimum area?
7. x²/m+2+y²/3-m=1 Let m = 2, the line L passing through point d (0,4) intersects curve C with two points m,. N, and O is the origin of the coordinate. If △ omn is a right triangle, the slope of L is obtained
8. It is known that the line L: x-y-1 = 0 and the circle C: (x-3) square + (y-4) square = 2 are tangent to point P and pass through point P Given that the line L: x-y-1 = 0 and circle C: (x-3) square + (y-4) square = 2 are tangent to point P, the line L1 passing through point P intersects circle C at another point Q, and the length of segment PQ is 2, the L1 equation is solved
9. If XY belongs to R and has 2x + y + xy = 6, then the maximum value of 2x + y?
10. Let p be a point on the ellipse x ^ 2 / A ^ 2 + y ^ 2 / b ^ 2 = 1 (a > b > 0) Given that point P is a point on the ellipse x ^ 2 / A ^ 2 + y ^ 2 / b ^ 2 = 1 (a > b > 0), F1 and F2 are the two focuses of the ellipse, and there is a point P on the ellipse, which makes ∠ f1pf2 = 60 degree 1. Calculate the value range of ellipse eccentricity 2. Calculate the area of △ pf1f2
11. It's difficult (for me) to ask two math problems of function (1) The function f (x) = x2 + 1 is a decreasing function on (- ∞, 0) (2) The function f (x) = 1-1 / X is an increasing function on (- ∞, 0) Yes, it's proof
12. Two questions about function mathematics 1. It is known that the image of the first-order function y = 3x-2k intersects with the image of the inverse scale function y = K-3 of X. the ordinate of one of the intersections is 6. Find the coordinates of the intersection of the image of the first-order function and the x-axis and y-axis 2. The analytic expressions of the inverse scale function to the first-order function are determined respectively when the intersection of the image of the inverse scale function y = x / K and the first-order function y = MX + n is a (- 3,4) and the distance from the intersection of the image of the first-order function and the X axis to the origin is 5
13. The image of a certain function passes through the point (- 1,3), and the value of function y decreases with the increase of the independent variable x. a function relation conforming to the above conditions is written out
14. As shown in the figure, we know that the image of the first-order function intersects the image of the positive proportion function at point m, intersects the x-axis at point n (- 6,0), and we also know the coordinates of point m (- 4,m). If the area of △ mon is 15, we can find the analytic expressions of the positive proportion function and the first-order function
15. It is known that the image of positive scale function y = KX and the image of primary function y = 4 / 3x + B intersect at point a (2,4), and the expression of primary function of positive scale function is obtained
16. In the plane rectangular coordinate system xoy, it is known that the line y = - x + 4 intersects with the X axis at point a, there is a point m on the line, and the area of △ AOM is 8, so the coordinates of point m can be obtained
17. Y = quadratic of X / quadratic of X + 1 (x belongs to R) Y value range
18. How to draw the image of the first-order function (e.g. y = 2x [0
19. For a linear function y = - 2x + 3, the value range of the independent variable X of its image in the first quadrant is? The answer is 0 ＜ x ＜ 3 / 2,
20. The image with positive scale function y = - 2x passes through the second step_________ In the quadrant, the function y increases with the increase of the independent variable x_______ It is known that the image of the linear function y = KX + 3 The image with positive scale function y = - 2x passes through the second step_________ In the quadrant, the function y increases with the increase of the independent variable x_______ It is known that if the image of a linear function y = KX + 3 passes through a point (- 1,2), then K=___________