I accidently hit enter so i posted twice my mistake. I can't say what we did in the week no more because all we do now is review.
So ill go over somehitn called the First derivative test
Steps: 1st take a derivative
2: set it =0
3: solve for x=>max mins, extrema , horizontal tangents
4: Set up intervals using step 3
5: plug in 1st derivative
6: If your finding absolute max/min plug values from 5 into original fuction
Example:
F(x)=(1/2)-cos(x) Find the extrema for f(x) on the (0,2pie)
f ' (x)=1/2-cos(x)
1/2-cos(x)=0
-cos(x)=1/2
x=cos^-1 (1/2)
x= pie/3, 5pie/3
b) 0,pie/3 pie/3 , 5pie/3 5pie/3 , 2 pie
then plug invalues b/w these sets
f '(pie/4)= 1/2-cos (pie/4)
which is decresing
b/w pie/3 and 5pie/3 it is increasing and b/w 5pie/3 and 2pie its decreasings
so pie/3 is a min
and 5pie/3 is a max
And im having trouble with disks and washers so if someone could help me thanks
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Ok, for disks, you are revolving only one graph about an axis. First set up an integral just as you normally would, square the whole equation and multiply it by pi.
ReplyDeleteEX: pi S (4x^3 + 3x)^2
For washers, you're going to have two equations. You set it up the same way as disks. The equation on top goes first minus the equation on the bottom
EX: pi S (4x^3 + 3x)^2 - (2x)^2
The only thing I could add to Mamie's wonderful explanation of the washers and disks would be to TAKE YOUR TIME! :)
ReplyDeleteThis is what messes a lot of us up