Tuesday, February 6, 2007

Lesson 8.6 Monday, February 6, 2007

Natural logarithms

4 comments:

Mrs. S. said...

Hello bloggers

Stacia Watts said...
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Stacia Watts said...

In lesson 8-6 you will be learning about natural logarithms.The objective is to evaluate natural logarithmic expressions and to solve equations using natural logs.Now, why would these expressions be important? They are useful because they help express many relationships in the physical world. The first example consists of simplifying natural logarithms. An example would be 5 ln 2-ln 4. You would begin this problem first by using the power property(log "base b" of m to the n power) to move the 5 above the 2. Then you will use the quotient property by writing: ln of 2 to the 5th power(32) above 4. When you reduce you should have the answer: ln 8. The rest of this lesson consists of "solving" natural logarithmic and exponential equations. I learned that to solve these problems you just need to follow simple steps.
Solving a log equation--
step1)Simplify until you have log base b of N=P
step2)Change to B to the P power=N
Solving an exponential equation--
Prequel:Simplify
1)Write log on both sides
2)Use power rule
3)Solve for x
*Other formula's you might need for this lesson will include: v= -0.0098t + c ln R.
*A=Pe raised to the rt power.
If you grasp these steps and use them for the basics of each problem you should have no problem understanding this lesson.

Anslee said...

Lsn 8.6 Natural Logarithms

When using natural logs, the base is e ( e=2.71828). This log is understood, so it will most likely not be visible in problems. Natural logs are notated with the letter "ln."

A natural Log function is y=e^x, and given that, the log(base e) y=x or lny=x.

** This chapter also informed us about the formula v= -.0098t + clnR
t-Time
c- Velocity of Exhaust
R- Mass w/ fuel/ Mass w/o fuel

ex: V=-.0098(100) + 2.8ln25
= 8.0km/s

ex: lnx^3 + lny
Use the Product rule
lnx^3y

ex:lnx=.1, (change B^p=n) e^.1=x
x=1.1052

*** Remember Lne= 1 !!!!!