Function (Domain and Range)

salam

Pre Cal~

Domain Range eh. ? many student find out that tis subtopic realy kill their nerve. however, i found that there are just a few 'thing' from all serabut thing that you must take a good remind of if you want to rekill tis subtopic

1) Graph of function
-reciprocal function
-square root function

2) in a root of a square, the root must be in the positive number (unless the question want it to be a complex number) we cannot square root of -1 , can we. ? unless it will be = i

3) any divisor cannot equal to 0


4) to find a range of a function we MUST inverse it


now, we will go to the realy 'easy' part, remembering/understanding the concept of the function.

now i will show u, why the 4 main points i mentioned above2 are the important thing that you must to understand.. see the picture below and look for the reciprocal function and square root function

1stly, we will go through the Reciprocal Function

and now we will see what happen to the domain and range when the divisor of the reciprocal 

have the power of 2.

and, why square root function i also took as a main point. ?

because, in the reciprocal function, there will be 98% when a divisor of a reciprocal has a power of 2, then its divisor of the inverse will became square root :p

i will not show you all the way to get the domain and range for the other function, because the other functions are just some basic from form4 and form5, 

kinda not use to explain in text, come see f2f, insyaAllah, if i can, i will explain till u satisfied.

as i go through this cute-tutorial-making.. i found out some more point..

5) the exact answer is in the interval form ( ) , [ ] , [ ) , ( ] , 

to find the domain and the range in the interval form, you must look for function f(x) and imagine how its shape, then you will see how this math-game played... lack of imagine hormone.. ? don worry, you can sketch the graph for the function :)

6) oh,, if you kinda have low term of memory to save all this knowledge, just stick with 1 fact.. 

you can always find a domain and range using substitution method (sketching the function)

7) domain : is the values of x : x

range : is the values of y :  f(x)

don't make small mistake cut your marks 

ps : adeh... cigu english aku baca entri ni,, sah sedih, macam tak penah ajar aku english pon.. terabur ja ayat

pss : study dengan terang kat orang len berkesan oh, so, sebab tu la aku cakap sorang2 dengan laptop ni haaaa :p

psss : segala penerangan adalah berdasarkan tajuk pre calculus.. kalau tajuk2 lain idk oke..

pssss : salah,, ? tolong la tegur!!

psssss : saje je nak update.. haha!