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[SOLVED] logarithm

siyanor

New member
Apr 6, 2012
8
I have an equation which answered it in two ways,which one is correct ?Problem1.GIF
 

SuperSonic4

Well-known member
MHB Math Helper
Mar 1, 2012
249
I have an equation which answered it in two ways,which one is correct ?
View attachment 163
The first method is not correct because ln(7.3) has simply disappeared.

The second method is correct but the rounded answer is not correct. $ x = \frac{1}{2}\left(\frac{\ln(10)}{\ln(7.3)}-1\right) \approx 0.0792 $
 

checkittwice

Member
Apr 3, 2012
37
I have an equation which answered it in two ways,which one is correct ?View attachment 163
[tex]7.3^{2x + 1} \ = \ 10[/tex]

siyanor,

(regarding the correct process of method #2),
because you have 10 on one side at that point,
that lends itself to taking log (base 10) of each
side:

[tex]\log_{10}7.3^{2x + 1} \ = [/tex][tex] \log_{10}10[/tex]


[tex](2x + 1)\log(7.3) \ = \ 1[/tex]


[tex]2x + 1 \ = \ \dfrac{1}{log(7.3)}[/tex]


And continue . . .