SOLUTION: If {{{ log(x, y^4) = m^3 }}} and {{{ log(y, x) = 4 / m^2 }}}, prove that m = 1.

Algebra ->  Logarithm Solvers, Trainers and Word Problems -> SOLUTION: If {{{ log(x, y^4) = m^3 }}} and {{{ log(y, x) = 4 / m^2 }}}, prove that m = 1.       Log On


   



Question 1178302: If +log%28x%2C+y%5E4%29+=+m%5E3+ and +log%28y%2C+x%29+=+4+%2F+m%5E2+, prove that m = 1.

Found 3 solutions by Solver92311, MathLover1, greenestamps:
Answer by Solver92311(821) About Me  (Show Source):
You can put this solution on YOUR website!




and



Therefore, if



Then



and

Eq 1:

Also if



Then

Eq 2:

Substituting the equivalent expression for from Eq 2 into Eq 1:



Simplifying:



Therefore:



John

My calculator said it, I believe it, that settles it

From
I > Ø

Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!

If +log%28x%2Cy%5E4%29+=+m%5E3+ and +log%28y%2C+x%29+=+4%2Fm%5E2+, prove that m+=+1

+log%28x%2Cy%5E4%29+=+m%5E3+
+4log%28x%2Cy%29+=+m%5E3+
+log%28x%2Cy%29+=+m%5E3%2F4+ ........change to base 10
+log%28y%29%2Flog%28x%29+=+m%5E3%2F4+ ...........eq.1


+log%28y%2C+x%29+=+4%2Fm%5E2+
+log%28+x%29%2Flog%28y+%29=+4%2Fm%5E2+
+log%28+x%29=+%284%2Fm%5E2+%29log%28y+%29
+log%28y+%29%2Flog%28+x%29=+1%2F%284%2Fm%5E2+%29..........eq.2

if left sides of eq.1 and eq.2 are same, then
+m%5E3%2F4=+1%2F%284%2Fm%5E2+%29
+m%5E3%284%2Fm%5E2+%29=+1%2A4

+m%5Ecross%283%29%284%2Fcross%28m%5E2%29+%29=+4

+m%2A4=+4
+m=1




Answer by greenestamps(13200) About Me  (Show Source):
You can put this solution on YOUR website!


Note that the two equations involve log%28x%2Cy%29 and log%28y%2Cx%29. Somewhere in working the problem you are going to want to use this property of logarithms:

log%28y%2Cx%29+=+1%2Flog%28x%2Cy%29

Work with the first equation:

log%28x%2Cy%5E4%29=m%5E3
4%2Alog%28x%2Cy%29=m%5E3
log%28x%2Cy%29=m%5E3%2F4
log%28y%2Cx%29=1%2F%28%28m%5E3%2F4%29%29=4%2Fm%5E3

Now look at the second equation:

log%28y%2Cx%29=4%2Fm%5E2

The two expressions for log%28y%2Cx%29 must be equal:

4%2Fm%5E3=4%2Fm%5E2
4m%5E3=4m%5E2
m=1