SOLUTION: Can you pls help me with the following: Use the Change of Base Formula to evaluate each expression. Leave your answer in "calculator ready" format. log_2⁡7 Thank yo

Algebra ->  Logarithm Solvers, Trainers and Word Problems -> SOLUTION: Can you pls help me with the following: Use the Change of Base Formula to evaluate each expression. Leave your answer in "calculator ready" format. log_2⁡7 Thank yo      Log On


   

Question 409819: Can you pls help me with the following:
Use the Change of Base Formula to evaluate each expression. Leave your answer in "calculator ready" format.
log_2⁡7
Thank you!!
Answer by jsmallt9(3758) About Me  (Show Source):
You can put this solution on YOUR website!
log%282%2C+%287%29%29
No calculator I know of :knows" base 2 logarithms. So the only way to express this logarithm in a way that your calculator can handle is to use the Change of Base Formula to change this base 2 logarithm into an expression involving logarithms your calculator does "know", like base 10 or base e (aka ln).

The Change of Base Formula is:
log%28a%2C+%28p%29%29+=+log%28b%2C+%28p%29%29%2Flog%28b%2C+%28a%29%29
We can use this to change to base 2 logarrthm into an expression of base 10 logarithms:
log%28%287%29%29%2Flog%28%282%29%29
or base e logarithms:
ln%287%29%2Fln%282%29

Note: If you actually calculate both of these expressions you will find, believe it or not, that they are equal!