How to judge parity of mathematical function in grade one of senior high school Fast judgment of parity

How to judge parity of mathematical function in grade one of senior high school Fast judgment of parity


Use f (- x) to replace all x in the formula, and use - x to replace all x in the formula. If the absolute value and square can not affect the change of X, the final result is f (x) ~ which is even function
If the influence formula cannot be unified with the original formula, then the negative sign is extracted. The formula - f (x) is an odd function. It should be noted that the odd and even function is about (0,0)
Note that symmetric about the y-axis are non odd and non even functions



For the function f (x) defined on R, three propositions are given: (1) if f (- 2) = f (2), then f (x) is even function; (2) if f (- 2) ≠ f (2), then f (x) is not even function; (3) if f (- 2) = f (2), then f (x) must not be odd function______ .


According to the definition of even function, for any value in the domain of definition, f (- x) = f (x) is satisfied. For ①, only f (- 2) = f (2) is satisfied, which does not mean that it is true for other values on R, so ① is wrong. For ②, the converse proposition is: if f (x) is even function, then f (- 2) = f (2) is true, so



What are the addition, subtraction, multiplication and division of increasing and decreasing functions?


At any time, there is an increase + increase = increase decrease = increase + decrease = decrease increase = decrease. When the function is greater than 0, there is an increase * increase = increase / decrease = increase / decrease * decrease = decrease / increase = decrease. Others cannot be determined



How to judge function parity
In addition to rigorous mathematical reasoning, whether the parity of function can be judged by visual observation. The need of symmetry in Higher Mathematics integral


First of all, the function whose domain is symmetric to the origin may be odd or even. The function whose domain is not symmetric to the origin must be non odd and non even. For example, y = x & # 178; (x-1



Judgment of function parity
For example, f (x) is an odd function, why f (- k * 3 ^ x) = - f (k * 3 ^ x) instead of F (k * 3 ^ (- x)) = - f (k * 3 ^ x)


The definition of odd function is that if f (- x) = - f (x) or F (x) / F (- x) = - 1 for any X in the domain of function f (x), then function f (x) is called odd function
Here x refers to the whole in brackets, not just the letter X on the surface
Personal understanding^_^



To judge the parity of a function, it is necessary to use the process
fx={x^2-2x (x>=0)
x^2+2x (x


A:
X is in the real range R
f(0)=0
When x > 0, - x



The sum of two decimals is exactly the product of their multiplication?


3.5+1.4=3.5×1.4
These two numbers can be 3.5 and 1.4
2.25×1.8=2.25+1.8
These two numbers can also be 2.25 and 1.8
……
There are countless



What is the sum, difference and quotient of an integer added, subtracted and divided by itself equal to 35


Let this number be X
2x+1=35
x=17



A number is added, subtracted, and divided by itself. The sum, difference, and quotient are added again. The sum is 8.6. What is the number?


This number is x; from the meaning of the paper, you can get: (x + X + X + X (x + x) + (x-x-x) + (x-x-x) + (x-x-x-x) + (x-x-x (x-x) + (x-x-x) + (x-x-x) + (x-x-x (x-x-x) + (x-x-x) + (x-x-x \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\- 1 = 8.6-1, & nbsp; & nbsp; & nbsp; & nbsp;                   2x=7.6,                   2x÷2=7.6÷2,                   &X = 3.8. A: this number is 3.8