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The square of inequality - x plus 2x minus 3 > 0 Just the answer
-The square of x plus 2x minus 3 > 0
-(x-1) ^ 2-2 > 0 has no solution
X ∈ empty sets
The square of minus x plus 2x minus 3 is greater than 0
-x^2+2x-3>0
x^2-2x+3
If the inequality [(1-A) n-a] LGA < 0 holds for any positive integer n, then the value range of a is______ ．
When a ＞ 1, LGA ＞ 0, so (1-A) n-a ＜ 0 holds; when 0 ＜ a ＜ 1, LGA ＜ 0, so (1-A) n-a ＞ 0 holds for any positive integer n; so the minimum value of (1-A) n-a ＞ 0; when n = 1, there is a minimum value of 1-2a ＞ 0, and the solution is a ＜ 12. So the answer is (0, 12) ∪ (1, + ∞)
If the number of a is divided by the number of B, the quotient is more than 7 A, and the number of a and B is increased by 5 times at the same time, and the remainder is ()
Number a x, number b y,
When x-a / y = 7, the numerator denominator is expanded 5 times, and 5x-5a / 5Y = 7, so the remainder a is expanded 5 times
3 △ 0.12 column vertical calculation,
The application of parametric equation of high school straight line and conic
Parametric equation x = 2 + 2 / T, y = 2 + 2 / T root sign three T, circular equation, X cottage + y cottage = 16, a small point P < 2,2 > on the line, intersection AB, find the absolute value of PA times the absolute value of Pb. Why is the opposite number of T1 times T2 the answer?
In the linear parametric equation, if the sum of squares of the coefficients of parameter t in X and Y is 1, then parameter t has geometric meaning,
That is to say, the length of the directed line segment from the point through which the line passes to the point corresponding to the parameter t is t
T is positive, indicating that the direction of the directed line segment is the same as the positive direction,
T is negative, indicating that the direction of the directed line segment is opposite to the positive direction
The length of a line segment is the absolute value of the length of a directed line segment, that is, the absolute value of T
Substituting the parametric equation into the circular equation, T ^ 2 + 2 (1 + √ 3) T-8 = 0
The two roots T1 and T2 of the equation are the lengths of the directed line PA and Pb
According to Weida's theorem, T 1 * t 2 = - 8, the opposite number (absolute value) is obtained
If there is no solution for the system of inequalities x < m + 3 and x > 2m-5, what is the range of M?
m+3≤2m-5
m≥8
How to calculate 87.53 + 0.99 and 87.53 + 1.01
How can we simply calculate it? 87.53 + 0.99 is 87.53 + 1-0.01
87.53 + 1.01 is 87.53 + 1 + 0.01
If the first n terms of the arithmetic sequence {an} and Sn are known Lim [Sn / (n & # 178; + 1)] = - A1 / 8 (A1 > 0), then n is the maximum value of Sn=__
Let an = a1 + (n-1) d
There is Sn = Na1 + n (n-1) d / 2
limSn/(n^2+1)
=lim[na1+n(n-1)d/2]/(n^2+1)
=lim[a1/n+d/2-d/(2n)]/(1+/n^20)
=[0+d/2-0]/(1+0)
=d/2
So D / 2 = - A1 / 8, d = - A1 / 4
an=a1+(n-1)d=a1-(n-1)a1/4
Obviously, the maximum value can be obtained by adding all the positive or non negative numbers. If you add a negative number, it will decrease, so
an=a1-(n-1)a1/4≥0
Because A1 > 0, 1 - (n-1) / 4 ≥ 0
n≤5,
When n = 5, A5 = 0
So when Sn reaches the maximum, n = 4, or n = 5
How to calculate the coefficients of polynomials in the matrix? In the following formula, how to calculate the coefficients of x ^ 4 and x ^ 3?
| 2 x 3 x|
| 3 4 2x 3|
| 1 x 5 1|
|5x 2 x 4|
The matrix itself is the coefficient of the polynomial. If there is a corresponding polynomial value behind it, four equations can be listed to solve the value of the unknown. Only determinant can be calculated
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