Saturday, February 13, 2010
The Function f(x) from the graph f '(x)
The function f(x) is decreasing in the interval (-infinity,-2) U (2, infinity), because a function is decreasing when the slope is negative.
2. There is local minimum at x=-2. Extremas can be found in critical points when f '(x)=0 or undefined. x=-2 is a local minimum because the slope of f(x) changes from being negative to positive.
There is local maximum at x=2 because at this point the slope of f(x) changes from being positive to negative.
3. The function is concave up in the interval (-infinity, -5/4) U (0,5/4). A function is concave up where f ''(x)>0.
The function is concave down in the interval (-5/4,0) U (5/4, infinity). A function is concave down where f ''(x)<0.
I can tell from the graph f ' (x) where f ''(x) is positive and negative by looking where the slope is positive and where the slope is negative since f ''(x) is derivative of f ' (x).
4. f(x) is a power function of 5 because the graph of f '(x) is to the power of 4 so its anti-derivative has to have a power of five.
Thursday, January 14, 2010
Growth vs. Fixed
1. Which mindset do you think you are a part of when it comes to "intelligence"? According to the reading, what tells you that you are of this mindset?
I consider myself to have a growth mindset when it comes to intelligence typically because I always tell myself that the more you know the smarter you get but also have some characteristics of a fixed mindset. In the reading a person who has a growth mindset is described as someone who does not back down from challenges. I take challenges to see how strong I am in a certain area but am also cautious about the challenges I choose. I always try to learn from people who have had success to see if there is anything I can relate to.
2. How has this mindset helped or hurt you in math?
A growth mindset has helped me put an effort into my work such as like in math problems. I always make things as simple as I can make them because the simpler it is the easier it gets.
I was not very surprised because the brain is just like any other muscle the more you put it to the challenge the stronger it gets. Some people train their muscles (brains) more than others which are why some are more successful than others.
The more a person works at something the better the outcome is. This information will help me in being able to understand others by considering the way they think.
Saturday, December 19, 2009
Algebra vs. Calculus
The two cases are the same when the function is continuous were the limit when x approaches c is the same as the value of the function when x=c.
2. The similarities when finding the derivative of a line and the slope is that the value is the same in the case of a line because in both functions you are finding the change in y over the change in x. In a derivative when finding the value we use limit as h approaches 0 f(a+h)-f(a)/h meaning that we are assuming that the difference as h approaches a is infinitely small.
Derivatives are mainly used to find the slope of a point in a curve by finding the slope of its tangent line.
Tuesday, December 8, 2009
Limits
One of the biggest problems I have is trying to figure out End behavior models for trigonometric functions without using a calculator for example problem number 38 on pg 95 which is f(x)=ln[abs(x)]+sinx. I was able to figure out the right end behavior model knowing that sinx was not really significant because the smallest value is -1 and that the biggest value is 1 so I knew that ln[abs(x)] was the right end behavior model.
I still have trouble in trying to figure out how to solve for horizontal asymptotes for a function. I am not sure whether there is a way to solve for it without having to graph it.
I was really confident about the limits test after seeing the practice test we got primarily because I did not see anything that gave me too much problem. After taking the test I was blindsided by a couple of problems on the test which is still bugging me that I was not able to solve which was one about explaining why a trigonometric function was continuous and to graph a sketch. The other one was the free response which had a piecewise function with a function having a variable on it.
Tuesday, November 24, 2009
Life after high school
Saturday, November 21, 2009
Tips and Hints
Saturday, November 14, 2009
Logs and Inverses
Another major concept I understood was the rules of exponents and logarithms for example in logs- log (XY)=log (X) + log (y) , log (X^5)=5log(x), log (X/Y)=log (X)-log(Y). these rules allow you to write and manipulate logs in many different forms. For example you can manipulate log (10) into log (5)+log (2)=log (5x2)=log (10). These rules are very helpful when trying to find a value in an exponential equation or in a logarithm.
A very important concept that I understood about inverses and functions is that f(f^-1(X))=x and f^-1(f(x))=x. This is very helpful in checking whether or not an inverse function is the inverse of a function. I also understood that a function has to pass the vertical line test which states that if a vertical line was passed through a graphed function it should only intersect the function at one point as seen in the image.
A function that is one-to-one is any function that passes the horizontal and vertical line test which means it is any function that has an inverse. Passing a horizontal line test on a function is the same thing as passing a vertical line test on its inverse function. Graphically when a function is graphed its inverse will be symmetrical to line y=x.
I had some trouble in trying to figure out an answer to a math problem we got in our homework pg 44 number 35 & 36. I am not really sure whether there are different rules when solving an exponential function that has addition on it.