关于数学,英文数学题, 急!!!!!!!!!!!!!!!!

来源：百度知道 编辑：UC知道 时间：2024/05/26 14:46:48
Find the inverse, g(x), of the function: f : R ® R defined by
f(x) = -17 x - 26

Answer:

Find the inverse, g(x), of the function: f : {x Î R : x > -18/17} ® R defined by
f(x) = ln(68 x + 72)

Answer

Enter your answer as one of the letters i,s,b,r, (capital letters NOT ALLOWED) :

i(njective) to indicate that the relation is an injective (but not bijective) function
s(urjective) to indicate that the relation is a surjective (but not bijective) function
b(ijective) to indicate that the relation is a bijective function
r(elation) to indicate that the relation is not a function, just a relation

In each of the following cases classify the relation:

4.1
The relation { [a4,a2],[a2,a3],[a7,a7],[a3,a4] } from { a7,a3,a4,a2 } to { a7,a3,a4,a9,a2 }

Answer:

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4.2
The relation { [a4,a2],

第一题就是让你求个f(x) = -17 x - 26 的反函数。
So the answer is: g(x)=-(x+26)/17

第二题也差不多，也是求反函数，不过加了个定义域罢了：x > -18/17
So the answer is: g(x)=(exp(x)-72)/68, where the domain of x is (-inf,inf) 注："inf"指"无穷大"

4.1-4.3的都是让你判断单、满、双射或“无等价”关系的。只要知道定义，很容易判断的。So the answers are:
4.1 injective(非满射是因为值域里的a9没有对应的映射)
4.2 relation (那是因为：[a2,a7]和[a2,a9]，同一个a2射到了2个值，不符合“函数”的定义）
4.3 bijective(很显然，既是单射又是满射，所以是双射)

第一题就是让你求个f(x) = -17 x - 26 的反函数。
So the answer is: g(x)=-(x+26)/17

第二题也差不多，也是求反函数，不过加了个定义域罢了：x > -18/17
So the answer is: g(x)=(exp(x)-72)/68, where the domain of x is (-inf,inf) 注："inf"指"无穷大"

4.1-4.3的都是让你判断单、满、双射或“无等价”关系的。只要知道定义，很容易判断的。So the answers are:
4.1 injective(非满射是因为值域里的a9没有对应的映射)
4.2 relation (那是因为：[a2,a7]和[a2,a9]，同一个a2射到了2个值，不符合“函数”的定义）
bf