What is the inverse of y=3log(5x)-ln(5x^3)y=3log(5x)ln(5x3)? ?

1 Answer
Jun 22, 2016

y = 1.33274 xx10^((-0.767704 x)/3)y=1.33274×100.767704x3 for 0 < x < oo0<x<

Explanation:

Supposing that log a = log_{10}a, ln a = log_e aloga=log10a,lna=logea

For 0 < x < oo0<x<

y = log_e(5x)^3/log_e 10-log_e(5x)^3+log_e 25y=loge(5x)3loge10loge(5x)3+loge25

y log_e10 = (1-log_e10)log_e(5x)^3+log_e25 xxlog_e 10yloge10=(1loge10)loge(5x)3+loge25×loge10

log_e(5x)^3=(y log_e10 - log_e25 xxlog_e 10)/ (1-log_e10)loge(5x)3=yloge10loge25×loge101loge10

(5x)^3=c_0e^{c_1y}(5x)3=c0ec1y

where c_0 = e^(-(log_e25 xxlog_e 10)/ (1-log_e10))c0=eloge25×loge101loge10
and c_1 = log_e10/(1-log_e10)c1=loge101loge10

Finally

x = 1/5 c_0^{1/3} xx e^{c_1/3 y}x=15c130×ec13y

or

x = 1.33274 xx10^((-0.767704 y)/3)x=1.33274×100.767704y3

Red y=3log(5x)-ln(5x^3)y=3log(5x)ln(5x3)
Blue y = 1.33274 xx10^((-0.767704 x)/3)y=1.33274×100.767704x3

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