Post #12

Ok so week 12 of Calculus is over with. This week was stressful let me just say that! We’re going over everything once again and for some reason I’m STILL unable to grasp a lot of the problems. We had the packets that were due Friday [today] on all of the stuff we needed help on. It helped me a lot on my test. Our test was broken up into two parts, the multiple choice one day and the free response the next. Goshh…… I’m glad I did okay on the multiple choice because I know I did pretty badly on the free response. I don’t know why but I just blanked when I got the test in my hand. 
After taking the multiple choice part of the test I realized I might have a chance, so I went home and studied everything that I didn’t understand once again. WOW all that work for nothing. After the test was over with we were all relieved. However, today Mrs. Robinson told us that we did HORRIBLE on the limits part, so we got a packet on limits today. I LOVE LIMITS PERSONALLY because that’s one of the things I feel confident on...Ha!
So I guess I can explain limits right.
Umm let’s say you have to find the limit of x = 4 with some equation, all you have to do is plug the equation into your y= part of your calculator and remember if you have a fraction that the numerator and the denominator are in parenthesis because the calculator needs to know what’s with what. After that press second graph in order to get to table and remember that your table set function should be set to ask on independent. If its x=4 for the limit you’re trying to find, plug in 4-.1…4-.01…4-.001…4+.001…4+.01…4+.1… and the answers you get is what you look at to find the answer. You look at all the – and all the + and whatever they are going to is what the limit is!
If you have x=4ֿ then you just plug in the minus’s and see what it’s going to, and for x=4(+) then you would just plug in the plus’s and see what it’s going to.
Remember all the rules for the limit going to 0 and to infinity!! WE NOW HAVE THAT IN OUR NOTES FROM TODAY!
Just a review:
• a differential is when something is solved for dy or dx like:
y=cos(x)---solve for dy
dy/dx = -sin(x)
dy = [(dx)*(-sin(x))]
• When we use differentials to approximate there are steps involved:
1. Identify Equation
2. f(x) + f'(x)*dx
3. determine dx
4. determine x
5. Plug in and solve!
For example: (number one on the Approximate part of our wednesday night
homework) to approximate the square root of 99.4 we use the
steps...
~the equation is -- f(x) = the square root of (x)
~the square root of [x] + [(1)/(2 * the square root of [x]) multiplied by (dx)]
~ dx = .4
~ x = 99
~ plug in: [the square root of 99] + [(1) / (2 * the square root of 99) multiplied
by (.4)]
~when solved:....9.96997, the error is 0.0002