Hey its Chris!

Today, we started off precal by Mr.P giving us his advice on his new gadget called "nook" as he said it can hold a lot of books i believe Mr.P's has like over 200 books on it, is it not very expensive around the price of $175.00. Anyways today we learned all about Distance between Points and Lines. We did a total of 5 examples for the book calculating Horizontal Distance, Vertical Distance and Shortest distance.

Here is Example 1: Calculate the distance from the point (2 , 3) to the line y=2x + 4.

Step 1: 2x-y+4=0
Move y to the other side and equal everything to 0.

Step 2: Determine your A,B,C values then use the Distance Formula to solve the equation.

A=2 , B=-1 , C= 4

Distance

Formula:

$eq=\frac{Ax_1 +By_1 + C}{\sqrt{A^2 + B^2}}$

Step 3: Substitute in the A,B,C values into the equation.

$eq=\frac{2(2) +(-1)(3) + 4 }{\sqrt{(2)^2 + (-2)^2}}$

Step 4: Solve the equation.

$eq=\frac{4-3+4}{\sqrt{5}}$

Step 5: Rationalize the denominator.

$eq=\frac{5}{\sqrt{5}}$

Step 6: Multiply by 5 to get rid of the denominator.

$eq= \frac{(5)\sqrt{5}}{5}$

Final Answer: Distance =

$eq= \sqrt{5}$

I hope the helped in some way... Mr.P did assign us homework which was Exercise 22, Questions 1-4, 6, 7, 9-12 which you should not forget to do. A little message to Sarah, Hello and i am sure you are watching for new posts every minute of the day. Good-Night class mates... :)

Pre - Calculus 30S Fall 2010

Thursday, December 9, 2010

Hey its Chris!

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