Sunday, January 31, 2010

Ash's 24th Post

Uhhmm...fun fact for this week...I don't think I remember one..sorry!

I'm gonna explain a few of the problems on the AP that we had to correct ourselves :)

2. lim sin(pi/2+h)-1
h->0 h

Mrs. Robinson explained this to me, so I'll try to explain it back to y'all.
What's the first thing you see? Definition of a Derivative, right? Right!
You're on the right track!
So what do you do? Take the derivative of sin!
sin(pi/2)
=
cos(pi/2)
=
0!!
That's your answer :)


Number 7!!
A relative maximum value of the function (lnx)/(x) is....

Okay, I think I got Trina's help on this one, but it looked fairly simple when I just looked at it :D

You take the derivative of lnx/x
=
(1)-(lnx)/(x^2) = 0
Set your top equal to zero since that's all that you're worrying about anyway
1-lnx=0
Solve for x
lnx=1
x=e
y=lne/e = 1/e
TaDa!!



I need extreme help on problems like number 19!
Suppose the graph of f is both increasing and concave up on A less than/equal to X less than/equal to B. Then, using the same number of subdivisions, and with L, R, M, and T denoting, respectively, left, right, midpoint, and trapezoid sums, it follows that
A) R <= T <= M <= L
B) L <= T <= M <= R
C) R <= M <= T <= L
D) L <= M <= T <= R
E) NOTA


Also, I think I'm afraid of fractions. I know how to work some of them, but...I dunno =/ Can someone clarify these please?
For fractions:
Derivative: quotient rule, got it :)
Integration: ????
Solving for x when it's in the fraction: ????

that's all I can think of at the moment :)

Oh, btw...I'm SUPER terrified of that Free Response tomorrow v.v

2 comments:

  1. okay...solving for x in a fraction

    if you have (x)^2 - 2 divided by 23 equals 1,
    to solve for x you times both sides by 23 giving you
    (x)^2-2 equals 23
    add two to both sides
    giving you
    (x)^2 equals 25
    take the squareroot of both sides
    giving you x=5

    hope this helps! =)

    ReplyDelete
  2. for fractions when you are trying to integrate you have to use substitution..most of the time.

    but, if you think you can make it a negative exponent..for example, like if the bottom is squared, then you can make it a negative exponent to bring it to the top.

    ReplyDelete