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Function y = ln x (0
y∈（-∞,0）
Because the base number and the true number (you know what they mean?) one is greater than one, the other is greater than 0 and less than one, so their combined value is less than 0
y=ln x ,e＞1, 0
The range of function f (x) = ln (3 ^ x + 1) is
3 ^ x > 0 so 3 ^ x + 1 > 1 so ln (3 ^ x + 1) > = 0 so the range is [1, + infinity]
The range of the function f (x) = 3 over (3 ^ x-3) is
(-∞,-1)∪(0,+∞)
How to solve these equations with absolute value sign like | 2x + y + 1 | = | 2x + y + 5 |?
Another example is: how to translate "1-3k" = "3k-5" into "1-3k = ± (3k-5)"
3x-y+3=0,
|How to solve the system of equations 3x + 4y-17 | / 5 = 4?
Method 1 is suitable for students who have just come into contact with absolute value. Let a = 2x + y, and the original equation be changed to: | a + 1 | = | a + 5 | then it is transformed into the form of the second question you asked. Because it has absolute value, it may be positive or negative. Then, let's start to remove absolute value: change to: ± (a + 1) = ± (a + 5). At this time, there are four alternative ways: 1
If the absolute value a equals 8, then a equals 8
Plus or minus 8
If the absolute value of a is 8, the absolute value of B is 5, and a plus B is greater than 0, find the value of a minus B
If IAI = 8, then a = 8 or - 8
If IBI = 5, then B = 5 or - 5
It is known that a + b > 0
Then a ≠ - 8, so a = 8
So A-B = 8-5 = 3
Or 8 - (- 5) = 13
So the value of a minus B is 3 or 13
Write all integers with absolute values greater than 3 and less than 8
4,-4,5,-5,6,-6,7,-7
How many negative integers with absolute values greater than 1 and 3 / 4 and less than 6 and 7 / 8
6
Given the function f (x) = (SiNx − cosx) sin2xsinx. (1) find the domain of definition and the minimum positive period of F (x); (2) find the monotone decreasing interval of F (x)
(1) The definition of F (x) is {{x \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\4 ≤ 2K π + 3 π 2, X ≠ K π (K ∈ z) the monotone decreasing interval of K π + 3 π 8 ≤ x ≤ K π + 7 π 8, (K ∈ z) ≠ f (x) is: [K π + 3 π 8, K π + 7 π 8] (K ∈ z)
The function y = | SiNx | - 2sinx can be discussed as follows: when SiNx ＞ = 0, y = ︱ SiNx - 2sinx = - SiNx; when SiNx ＜ 0, y = ︱ SiNx
When SiNx ＞ = 0, y = ｜ SiNx ｜ - 2sinx = - SiNx; when SiNx ＜ 0, y = ｜ SiNx ｜ - 2sinx = - 3sinx
I don't understand how it came out
Because - 1
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