Given the function f (x) = x2 + 2aX + 2, X ∈ [- 5,5] (1) when a = - 1, find the maximum value of the function; (2) find the value range of the real number a, so that y = f (x) is a monotone function in the interval [- 5,5]; (3) find the minimum value of y = f (x)
(1) When a = - 1, f (x) = x2-2x + 2 = (x-1) 2 + 1, | when x = 1, f (x) min = f (1) = 1; when x = - 5, f (x) max = 37; (2) ∵ the image of F (x) = x2 + 2aX + 2 is parabolic, and the opening is upward, and the axis of symmetry is x = - A; (3) ∵ the image of F (x) = x2 + 2aX + 2 is parabolic, and the opening is upward When a ≥ 5, f (x) is an increasing function on [- 5,5]; when a > a > - 5, f (x) min = f (- 5) = 27-10a; when 5 > a > - 5, f (x) is a decreasing function on [- 5,5]; when a < - 5, f (x) min = f (- a) = - A2 + 2; when a ≤ - 5, f (x) is a decreasing function on [- 5,5]; when f (x) min = f (5) = 27 + 10A; therefore, the minimum value of f (x) on [- 5,5] is: F )min=27−10a(a≥5)−a2+2(5>a>−5)27+10a(a≤−5).
RELATED INFORMATIONS
- 1. For any differentiable function f (x) on R, if (x-1) f ′ (x) ≥ 0, then () A. f(0)+f(2)<2f(1)B. f(0)+f(2)≤2f(1)C. f(0)+f(2)≥2f(1)D. f(0)+f(2)>2f(1)
- 2. Ask a math problem (about high school function), It is known that the function y = f (x) defined on R satisfies f (0) ≠ 0. When x > 0, f (x) > 1, and for any a, B ∈ R, f (a + b) = f (a) f (b) (1) Verification: F (0) = 1; (2) Proof: for any x ∈ R, f (x) > 0; (3) It is proved that f (x) is an increasing function on R
- 3. Mathematical problems of high school function If the function f (x) = (k-1) a ^ x-a ^ (- x) (a > 0 and a ≠ 1) is both odd and even on R, then the image of G (x) = loga (x + k) is A. Monotonically decreasing at (- 2, + ∞) B. Monotonically increasing at (- 2, + ∞) C. Monotonically decreasing at (2, + ∞) D. Monotonically increasing in (2, + ∞) The title must be right!
- 4. I'm in a hurry If f (x) is an odd function with a period of 5, and f (- 3) = 1, Tan @ = 2, then f (x) is an odd function with a period of 5( 20sin@cos@ )What is the value of? The monotone decreasing interval of function y = LG [radical 3-2sin (Π / 6 - 2x)] is?
- 5. It is composed of two three digit numbers 0123456789. The sum of these two numbers must be four digits. These 10 numbers must be used completely and cannot be repeated
- 6. Some math problems, 3Q 1. A rectangular ventilation pipe, 4 meters long, with a cross section of 80 cm square. How many square meters of iron sheet is needed to make 100 such ventilation pipes? 2. There are two cubes whose edges are both 15 cm long. Put them together into a cuboid. The surface area of the cuboid is less than the sum of the original two cubes () 3. The total length of the edges of a cuboid is 80 cm, the length is 10 cm, the width is 7 cm, and the height is () cm
- 7. Little Red Riding Hood carried a basket of eggs to sell in the city. She sold half and one of all the eggs for the first time, half and one of the remaining eggs for the second time, and half and one of the remaining eggs for the third time. At this time, there was still one egg left in the basket. How many eggs were there in the basket?
- 8. Third grade math problem! Help to solve the next When Xiaoqiang was 12 years old, he only had three birthdays. Guess he was born on () month () and his birthday was in () quarter
- 9. 1. A ^ 2-9b ^ 2 + a-3b 2. M ^ 4-4m ^ 3 + 4m ^ 2-9 3.4x ^ 2-5x-6 4. (x + y) + 2 (x + y) - 15 5.2a ^ 2-4ab + 2B ^ 2-A + B-3 2. (x ^ 2 + x) (x ^ 2 + X-5) + 6,
- 10. In the isosceles triangle ABC, the opposite sides of the angles a, B and C are a, B and C respectively. It is known that a = 3, B and C are the two real roots of the equation x * + MX + 2-1 / 2m = 0 about X. find the circumference of the triangle ABC (* means square, 30 minutes)
- 11. 1. If f (x) = x ^ 2 + ax + 3, if x ∈ [- 2,2], f (x) ≥ a, find the range of A 2. For any x ∈ R, we know that f (x) + F (y) = f (x + y), and when x > 0, f (x) + F (y) = f (x + y), f(x)
- 12. Given that a, B ∈ R and a ≠ 2, the function f (x) = LG1 + ax1 + 2x defined in the interval (- B, b) is odd. (1) find the analytic expression of function f (x) and the value range of B; (2) discuss the monotonicity of f (x)
- 13. 1. A, B and c run the 100 meter race (assuming their speed remains the same). When a reaches the finish line, B is still 20 meters short, and C is 25 meters away. How many meters short is C when B reaches the finish line? 2. The walking speed ratio of Party A and Party B is 13:11. If Party A and Party B start from a and B at the same time and walk in opposite directions, they meet in two hours. If they walk in the same direction, how many hours will it take for Party A to catch up with Party B?
- 14. 1. The construction workers need 4800 square bricks for paving the street square. If they use 80cm square bricks instead, how many are needed? 2. A train leaves Wuhan for Nanjing at 6:30 a.m. and runs 120 kilometers per hour. Can it arrive at 10:30 a.m. (the distance on the map is 2cm, and the scale is 1:9000000) 3. There are two containers. First fill the cone with radius of 5cm and height of 10cm with water, and then pour it into the cylinder with radius of 4cm and height of 10cm. What is the depth of water in the cylinder?
- 15. Mathematics problems in grade six of primary school As shown in the right figure, for a triangular cardboard, the ratio of two right angle sides AB and BC is 1:2, and ab is 6 cm long. If you rotate AB side as an axis for one circle, then the volume of the formed cone is () cubic cm
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- 17. 1. 2.5 times of a number is 45 times more than itself. What's the number? 2. There are 55 chickens in two cages. If one ninth of them is taken out of cage a and one seventh of them is taken out of cage B, the remaining chickens in the two cages are exactly the same? 3. There is a glass of sugar water, the weight ratio of sugar and water is 2:9, then add 4G sugar, the weight of sugar water is 92g 4. Solving equation 2、2/5×1/2-1/10x=1/6 Two fifths times one half minus one tenth times x = one sixth (*: not comprehensive)
- 18. 1. When someone bought an article, he paid the salesperson 50 yuan. The salesperson misjudged the decimal point of the price of the article and gave him 46.75 yuan. He said that he found too much. How much is the price of the article? If you add the divisor, divisor, quotient sum and the remainder, the sum is 43, the divisor is (), and the divisor is ()
- 19. 1.6/1 hour = () minutes 2.6.08 cubic meters = () cubic meters () cubic decimeters 3. A cylinder and a cone are of equal height and equal base. The sum of their volumes is 48 cubic centimeters, and the volume of this cone is () cubic centimeters 4. The side area of the cylinder is fixed, and the radius of the bottom is in direct proportion to () 5 ratio: 4.2:3 5cm: 30m Simplification ratio: 192:645.25:356/1:9/1 15 / 8:25 / 12 3T: 150kg Solution equation: 1.5x + 24 = 89 9 / 2 × 3 + 4x = 12 / 11 14 / 3x + 21 / 13X = 28 / 15 To find the ratio, simplify the ratio and solve the equation,
- 20. The classroom is paved with 1800 tiles, 40 cm long, 20 cm wide and 1 cm thick. How many square meters is the area of the classroom