Sunday, February 21, 2010
Math is Super
Sunday, January 31, 2010
Friday, January 29, 2010
Super sick scribe post
Hey y'all. This is Wednesday's (27th) scribe post. Enjoy!
Firstly, we went over the quiz because a number of us did not do so hot. I was personally upset with myself for missing the first problem in which we were given a point of a function and asked what the derivative was. The derivative of a point is the slope of the tangent line so all I had to do was draw the tangent line and find its slope by counting squares. I do not know how I missed such a simple problem. Hurray to Bru for lowering the effect of quizzes on our grades.
Secondly, in class we went over what an Explicit function is. An explicit function or equation is the form that we normally write or see an equation. It is an equation that defines Y as a function of X.
Ex. Y=2x+3
The expression on the right explains how Y is related to X. This is called an explicit equation because it comes from the same root as “explain”, which is precisely what it does.
An equation that is not set up in the “Y equals…” form, only implies that Y is a function of X and therefore, it is called an implicit function. Deriving an implicit function can be easier than deriving an explicit function depending on how the equation is set up. This is called implicit differentiation.
Ex. Y-2x=3
To derive an implicit function: You do not have to reset up the equation. You simply derive the terms in the equation and replace Y with Y’. Then solve for Y’ and the result is your derivative. Lets try it out.
Y-2x=3 The equation
Y’-2=0 taking the derivative of the terms using the power rule.
Y’=2 Solving for the derivative
It is as simple as that, especially when you take the derivative of such an easy equation. And we can check if this is right by finding the derivative explicitly.
Y=2x+3 The explicit form of the equation
Y’=2 Finding the derivative using the power rule.
Now lets try the last problem on the exploration we were supposed to finish for homework. First let us solve the problem explicitly.
Y3=X7 The equation
Y=X7/3 We must isolate Y for the right side to explain how Y is related to X. Now we derive
Y’=7/3X4/3 Power Rule
So lets see if this matches up with the result we get from implicit differentiation.
Y3=X7 The equation
3Y2 x Y’=7X6 We’ve derived the equation and multiplied all the Y terms by Y’
Y’=7X6/3Y2 We isolate Y’ so as to figure out what it equals
Y’=7X6/3(X7/3)2 We know from the explicit equation that Y=X7/3
Y’=7X6/3X14/3 Simplify and then simplify even more
Y’=7/3X4/3 Check
We must’ve done it right because Y’ prime equals the same thing when we solved the equation both explicitly and implicitly. Yay
So another day in the world of calcultopia comes to an end. Another battle won but many more lay in our path to the ultimate answer of calculus. $@… Or something like that. Next scribe is Winn Plot
J-tron foteen