What is the solution set of inequality 4x > 5x?

What is the solution set of inequality 4x > 5x?

4x-5x>0
-x>0
X
(-OO,0)
The process of solving limit lim3x ^ 2-1 / x ^ 2 + 4 = 3
Divide by X and 178;
=lim(3-1/x²)/(1+4/x²)
=(3-0)/(1+0)
=3
If the point P (3a + 2,4a) is inside the circle (X-2) + y = 1, then the value range of real number a is
A（-1/5,1/5）
B（0,1/5）
C（-1/5,0）
D（-1/10,1/10）
If the point (a, b) is inside the circle (X-2) ^ 2 + y ^ 2 = 1
The results are as follows:
(a-2)^2+b^2
Hello, the answer is a, the solution: because the point is in the circle, then the distance from the point to the center of the circle is less than 1, that is, the root ((3a + 2-2) square + (4a) square) is less than 1, the answer is a. I hope my answer will help you!
This kind of question should be solved quickly in the exam, and it's best to use the elimination method.
The difference between a and b lies in the range of (- 0.2, 0),
Take a = - 0.1, P is (1.7, - 0.4),
Then (X-2) ^ 2 + y ^ 2 = 0.09 + 0.16 = 0.25 < 1,
It shows that point P is inside the circle at this time. Therefore, B and D are excluded.
For a and C, we can also take a = 0.1, P = 2.3, 0.4,
At this time (x... Unfolds
This kind of question should be solved quickly in the exam, and it's best to use the elimination method.
The difference between a and b lies in the range of (- 0.2, 0),
Take a = - 0.1, P is (1.7, - 0.4),
Then (X-2) ^ 2 + y ^ 2 = 0.09 + 0.16 = 0.25 < 1,
In this case, the point B is also excluded.
For a and C, we can also take a = 0.1, P = 2.3, 0.4,
Then (X-2) ^ 2 + y ^ 2 = 0.09 + 0.16 = 0.25 < 1,
P is still in the circle, so exclude C
The correct answer is a. The calculation is not complicated, it can be solved in one minute.
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Detailed answers:
If P (3a + 2, 4a) is in the circle (X-2) ^ 2 + y ^ 2 = 0,
Then x = 3A + 2, y = 4A
There must be (3a + 2-2) ^ 2 + (4a) ^ 2 < 1
The results are as follows
25a^2＜1
a^2＜0.04
- 0.2 < a < 0.2
Using the knowledge of integral and factorization, it is shown that the value of (X & sup2; - 4) (X & sup2; - 10x + 21) + 100 must be nonnegative
Ten minutes, please
Original formula = (x + 2) (X-2) (x-3) (X-7) + 100
=[(x+2)(x-7)][(x-2)(x-3)]+100
=[(x²-5x)-14][(x²-5x)+6]+100
=(x²-5x)²-8(x²-5x)-84+100
=(x²-5x)²-8(x²-5x)+16
=(x²-5x+4)²
The square is nonnegative
So the original is nonnegative
f(x)=cos2x+1+√3sin2x
=2(sin2xcosπ/6+cos2xsinπ/6)+1
=2sin(2x+π/6)+1
When sin (2x + π / 6) increases, 2K π - π / 2
Change the following inequality into "x > a" or "X"
5x
(X-Y) & # - 2x + 2Y + 1 factorization factor
The square of (x-y-1)
If you take the middle - 2x + 2Y as - 2 (X-Y), it becomes a complete square
The equation x2 + Y2 + ax + 2ay + 2A2 + A-1 = 0 represents a circle, then the value range of a is ()
A. a＜-2B. -23＜a＜0C. -2＜a＜0D. -2＜a＜23
The equation x2 + Y2 + ax + 2ay + 2A2 + A-1 = 0 indicates that the circle 〈 A2 + 4a2-4 (2A2 + A-1) ＞ 0 〉 3a2 + 4a-4 ＜ 0, 〈 (a + 2) (3a-2) ＜ 0, 〈 − 2 ＜ a ＜ 23, so D is selected
The common factor of polynomial 10A (X-Y) 2-5b (Y-X) is______ .
∵ 10A (X-Y) 2 = 5 (X-Y) · 2A (X-Y), 5b (Y-X) = 5 (X-Y) · (- b); ∵ the common factor of the polynomial 10A (X-Y) 2-5b (Y-X) is 5 (X-Y)
-5x-6a or X
-5x-6
x＞2/3
-9X
Factorization: (x + y) &# 178; + 4 (X-Y) &# 178; - 4 (X & # 178; - Y & # 178;)
(x+y)²+4(x-y)²-4(x²-y²)
=(x+y)²-2×(x+y)(x-y)+[2(x-y)]²
=[(x+y)-2(x-y)]²
=(x+y-2x+2y)²
=(x-3y)²
(x+y)²+4(x-y)²-4(x²-y²)
=x²+y²+2xy +4x²+4y²-8xy -4x²+4y²
=x²+9y²-6xy
=(x-3y)²