Inequality (15 14:54:28) The minimum value of the function y = 3x2 / 16 + 3 / X (x is greater than 0) is  

Inequality (15 14:54:28) The minimum value of the function y = 3x2 / 16 + 3 / X (x is greater than 0) is  

x=2
y=9/4

In the plane rectangular coordinate system xoy, it is noted that the quadratic function f (x) = x2 + 2x + B (x ∈ R) has three intersections with the two coordinate axes. The circle passing through the three intersections is denoted as C. (1) find the value range of the real number B; (2) find the equation of the circle C; (3) ask whether the circle C passes through a fixed point (its coordinates have nothing to do with B)? Please prove your conclusion

(1) let x = 0, the intersection of parabola and y-axis is (0, b); Let f (x) = x2 + 2x + B = 0, B ＜ 1 and B ≠ 0 are obtained by B ≠ 0 and △ 0. (2) let the general equation of the circle be x2 + Y2 + DX + ey + F = 0, let y = 0 get x2 + DX + F = 0, which is the same equation as x2 + 2x + B = 0, so d = 2, f = B. let x = 0 get Y2 + ey + F = 0, the equation has a root B, and E = - B-1 is obtained by substitution +Y2 + 2x - (B + 1) y + B = 0. (3) circle C must pass through a fixed point. The proof is as follows: suppose that circle C passes through a fixed point (x0, Y0) (x0, Y0 does not depend on B), substitute the coordinates of the point into the equation of circle C, and transform it into X02 + Y02 + 2x0-y0 + B (1-y0) = 0 (*). In order to make (*) formula hold for all B satisfying B < 1 (B ≠ 0), there must be 1-y0 = 0. Combining (*) formula, we get X02 + Y02 + 2x0-y0 = 0, and solve x0 = 0y0 = 1 or x0 = − 2y0 = 1, it is found that (- 2,1) and (0,1) are on circle C, so circle C passes through the fixed points (- 2,1) and (0,1)

Use the 10 numbers of 0-9 (15:18:56:13)
How many 4-digit odd numbers can be made up of 10 numbers 0-9?

2240. Choose one of the five odd numbers as a bit; there are eight choices for thousands excluding zeros and ones; there are eight choices for hundreds excluding thousands and ones; there are only seven choices for tens. So, the answer is: 5 * 8 * 8 * 7 = 2240

Two right angles make a flat angle, right

Yes, you can imagine two 90 ° sides, a 180 ° right angle

The two sides of the corner are square______ Such an angle is called a flat angle

According to the concept of angle, the two sides of an angle form a straight line, and the angle formed is called a flat angle

The angle greater than the right angle and less than the horizontal angle is called angle (), and the angle less than the right angle is called angle ()

More than right angle less than flat angle is called obtuse angle, less than right angle is called acute angle

6: 00, the angle between the hour hand and minute hand is () degrees, the two sides of the angle form a (), such an angle is called a flat angle

6: 00, the angle between the hour hand and minute hand is (180) degrees, and the two sides of the angle form a line (line segment)

What is the half of a right angle? What angle is it? What angle is it from a flat angle to two thirds? What angle is it

90 × 1 / 2 = 45 degree acute angle
180 × 2 / 3 = 120 degree obtuse angle

(1) 2 / 3 of a right angle is () degrees. 5 / 6 of a horizontal angle is () degrees, which is an () angle. 3 / 8 of a horizontal angle is () degrees
(2) One third of an hour is () minutes, and five ninth of an hour is () minutes.

The right angle is 90 ° and 2 / 3 is 60 °
The horizontal angle is 180 ° and 5 / 6 is 150 ° respectively
3 / 8 is 67.5 degrees
2 / 3 of a right angle is (60), 5 / 6 of a horizontal angle is (150), which is a (blunt) angle, and 3 / 8 of a horizontal angle is (67.5)
1 hour = 60 minutes
In the same way
One third of an hour is (20) minutes, and five ninth of an hour is (100 / 3) minutes

An angle of 145 degrees is () degrees smaller than a horizontal angle and () degrees larger than a right angle. It is an () angle

An angle of 145 degrees is (35) degrees smaller than a flat angle and (55) degrees larger than a right angle. It is a (blunt) angle