Given the square of equation AX - X-5 = 0, one is greater than - 1, the other is less than - 1, find the value range of real number a

Given the square of equation AX - X-5 = 0, one is greater than - 1, the other is less than - 1, find the value range of real number a

Ax & # 178; - X-5 = 0 because one is greater than - 1 and the other is less than - 1. First, there are two (- 1) & # 178; - 4 (- 5 × a) > 0, and the solution is a ＞ - 1 / 20. When - 1 / 20 ＜ a ＜ 0, the opening is downward, f (- 1) ＞ 0, that is, a + 1-5 ＞ 0, and the solution is a ＞ 4, so there is no solution. When a ＞ 0, the opening is upward, f (- 1) ＜ 0, that is, a + 1-5 ＜ 0, and the solution is a ＜ 4

Let the equation x ^ 2-ax-4 = 0 have a solution on [0,4]. Find the range of real number a

Since the discriminant = A & sup2; + 16 ≥ 16, the equation always has two solutions
And because the product of the two = - 4 < 0
So as long as the larger one is on [0,4]
Let f (x) = x & sup2; - ax-4, then f (0) × f (4) ≤ 0
∴a≤3

A = {x | x2 = 1} B = {x | AX = 1} B belongs to a, find the value of real number a

First, a = {1, - 1}, B belongs to a, so a = + - 1
But also consider whether B is an empty set. Think for yourself

Calculator about trigonometric function calculation results are all wrong, how is this going on?

It's hard to say what the specific situation is
It could be the following
There are two kinds of angle units in some calculators, one is degree, the other is radian. Maybe your calculator has set radian as the angle unit, but you don't know. If you input the degree of angle, the result is definitely wrong. For example, if you want to calculate sin30 degree, you enter 30, and then press sin key, the calculated value is sin30 radian

Mathematics problems in grade three of junior high school
1. In rectangular ABCD, ab = 16cm, ad = 6cm, the moving points P and Q start from point a and C at the same time, and stop moving at the same time. Point P moves to point B at the speed of 3cmgs, and stops moving until point B; point Q moves to point d at the speed of 2cm / s?
2. A person invests 20000 yuan, and after one year, he withdraws 10000 yuan for various living expenses, and continues to invest the remaining 10000 yuan and profits. After one year, he obtains 13200 yuan (including the original 10000 yuan). What is the annual interest rate of the investment?
You
5555 ~ we're going to hand it in tomorrow!
Moo 蕶薍﹎﹎, I want to ask where the 5x comes from?

Question 1: let's meet 10 cm in x seconds
Square of (16-5x) + 6 * 6 = 10 * 10
256-160x + 25X square + 36 = 100
Square of 25X - 160x + 192 = 0
Square of b-4ac = 25600-19200 = 6400
X = 4.8 and x = 1.6
Question 2: I can't

The difference between the sum of binomial coefficients and the sum of various coefficients
The sum of the coefficients is the product of all the numbers before the unknowns. "The sum of the coefficients of the n-th power expansion of" (x + 3Y) is equal to the sum of the binomial coefficients in the (7a + b) 10 expansion, and the value of n is calculated. "This explains why: let X and Y take the n-th power of the coefficient sum of 4, and the sum of the quadratic coefficients is the 10 th power of 2, n = 5. Isn't the formula 2 ^ n when the sum of the binomial coefficients is calculated?

The sum of the binomial coefficients in your (7a + b) 10 expansion is 2 ^ 10. Your understanding is correct. It is the sum of the binomial coefficients
The n-th power expansion of (x + 3Y) is the sum of coefficients in front of X and y, which is not the sum of binomial coefficients. The n-th power expansion of (x + 3Y) is the sum of coefficients, which is to substitute X and y as 1 into the n-th power expansion of (x + 3Y) to obtain the n-th power expansion of (x + 3Y) with the sum of coefficients equal to 4

Given a + B = 3 / 2, ab = - 1, find (A-2) (b-2) + (a-b) 2

A + B = 3 / 2, ab = - 1,
（a-2）（b-2）+（a-b）2
=ab-2(a+b)+4+(a+b)²-4ab
=(a+b)²-2(a+b)-3ab+4
=9/4-3+3+4
=25/4

Using the image of quadratic function, we estimate the approximate roots of the quadratic equation x2-2x-1 = 0 (accurate to 0.1)

The root of the equation x2-2x-1 = 0 is the abscissa of the intersection of the function y = x2-2x-1 and the X axis. Make the image of the quadratic function y = x2-2x-1, as shown in the figure. From the image, we can see that the equation has two roots, one between - 1 and 0, and the other between 2 and 3. First, find the root between - 1 and 0. When x = - 0.4, y = - 0.04; when x = - 0.5, y = 0.25; therefore, x = - 0.4 (or x = - 0.5) is an approximate root of the equation , x = 2.4 (or x = 2.5) is another approximate root of the equation

6X plus 3 equals 9

There is a column of numbers: A1, A2, A3 If A1 = 2, then a2007 is ()
A. 2007B. 2C. 12D. -1

According to the meaning of the question: A1 = 2, A2 = 1-12 = 12, A3 = 1-2 = - 1, A4 = 1 + 1 = 2; period is 3; 2007 △ 3 = 669; so a2007 = A3 = - 1