## Thursday, March 12, 2009

### BOB..!?!?!

Hi everyone! I'm Trinh and this my first post so if i make any mistakes,which i would, free to comment and I'll fix it.

About this unit, first i got some troubles with the "+" and "-" sign in the sine and cosine functions but now I'm ok with that.

Two Functions : f(x) = AsinB(x-C)+D
g(x)= AcosB(x-C)+D

We could use these 2 functions to solve some problems and that's really "cool".
In those 2 functions, you must remember ( i saw everyone all noticed about this but i still repeat it) :
A : the amplitude: the distance of the max or min values from the Sinusoidal Axis.
B : determines the periods ( B is NOT the Period)
Period= or B=
C
: determines the horizontal shifts
C > 0 : the graph shifted to the right
C
<>
Warning
: Watch the sign of C

D : determines the vertical shifts
D > 0 : the graph shifted up
D
<>

And there are something about even and odd function

Remember that a function is even if its graph is symmetrical about the y-axis

f(-x) = f(x)

And a function is odd when its graph is symmetrical about the origin.
-f(x) = f(-x)

The reflection function of y = f(x) is y = f -1(x) (inverse function)

Warning: f
-1(x)

I think it's enough for me.
Just reminder again: pre-test tomorrow, friday 13 and test is on monday 16.

Good luck to you guys