Tutors Answer Your Questions about logarithm (FREE)
Question 70656: log_3(x) - log_9(x) = 2
First i changed the base, by doing a little basic
reasoning. Suppose
y = log_9(x)
Then
9^y = x
(3^2)^y = x
3^(2y) = x
2y = log_3(x)
y = log_3(x)/ 2
Now you have
log_3(x) - (1/2)log_3 = 2
but im stuck from here, please help me with solving trhe x? ironicly i know the answer is 81, but i came to that but doing trial and error log_3(79) - log_9(79) = 1.9877etc than log_3(81) - log_9(81) = 2. I am sure there is a much simplar way of dealing with this but i dont know how to deal with the x above.
Click here to see answer by Earlsdon(6287)  |
Question 70761: I must solve the following equation, and then round the answer to the nearest hundreth, while using the Log way. 1+8(0.43)^2u=3
I placed Log in front of both equations like 2uLog(0.43)=Log(3/9). However I keep getting a completely different answer than what the book has provided, which is .82. Please solve this solution, thanks.
Click here to see answer by Earlsdon(6287) |
Question 70761: I must solve the following equation, and then round the answer to the nearest hundreth, while using the Log way. 1+8(0.43)^2u=3
I placed Log in front of both equations like 2uLog(0.43)=Log(3/9). However I keep getting a completely different answer than what the book has provided, which is .82. Please solve this solution, thanks.
Click here to see answer by stanbon(57377) |
Question 72121: Hi, please could you give me a hand on these questions? I have tried hard but i can't find my way with proofs:
3i)Prove that log of m (in the base a) - log of n (in the base a) = log of (m over n)( in the base a).
4i)Prove that nlog of x (in the base m) = log of x to the power of n (in the base m).
5a)Prove that log of b (in the base a) = log of b( in the base 10) over log of a (in the base 10).
Thank you very much for your help!!!!
Click here to see answer by stanbon(57377) |
Question 73058: formula for measuring sound in decibals?
pick a sound give decibals of the sound, and explain what this measurment means.
If you could just give me an example that would be great this question has stumped me!!! Thank You!!
Click here to see answer by stanbon(57377) |
Question 72885: A psychologist finds that the percent p of retention in a group is subjects can be modeled by
p=log(10^68)/log(t+1)^20
where tis the time in months from the subjects' initial testing. Use the properties of logarithms to write the formula in simplest form, and determine the percent of retention after 5 months.
Click here to see answer by bucky(2189) |
Question 72740: Please help me solve the following:
A skin wound heals according to the function
N(t) – Noe -.12t, where N is the number of square centimeters of unhealed skin t days after the injury, and No is the number of square centimeters covered by the original wound.
A) what percentage of the wound will be healed after 10 days?
B) how long, to the nearest day, will it take for 50% of the wound to heal?
C) how long, to the nearest day, will it take for 90% of the wound to heal?
Click here to see answer by ankor@dixie-net.com(15659)  |
Question 73211: Solve for x: log (2 lower)(x+2) + log (2lower)x=3
log (2 lower)[x(x+2)] = 3
2^3=x(x+2)
8=x^2 + 2x
x^2 + 2x-8=0
(x+4)(x-2)=0
x=-4, x=2
log(2 lower)(-4 + 2) + log (2 lower) (-4)=3
this is where i get stuck and need some help. Thanks!
Click here to see answer by stanbon(57377) |
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