Question 68062
make x so that e^(-x/9) that is less than 0.1
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e^(-x/9)< 0.1
Take the natural log of both sides to get:
-(x/9) = ln(0.1)
-(x/9) < -2.3026
Multiply both sides by -1 to switch the inequality:
x/9> 2.3026
Multiply both sides by 9 to get:
x>20.7233
Cheers,
Stan H.