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If log(base 3) 4 is approximately 1.2619, evaluate log(base 3) .25. Give your answer...

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kristenmarieb... | Student, Grade 10 | Valedictorian

Posted August 16, 2013 at 4:05 AM via web

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If log(base 3) 4 is approximately 1.2619, evaluate log(base 3) .25.

Give your answer correct to four decimals.

Tagged with algebra2, math

2 Answers | Add Yours

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llltkl | College Teacher | Valedictorian

Posted August 16, 2013 at 4:30 AM (Answer #1)

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`log_3(0.25)`

`=log_3(25/100)`

`=log_3(25)-log_3(100)`   (since `log_a(m/n)` =`log_am-log_an` )

`=log_3(25)-log_3(4*25)`

`=log_3(25)-{log_3(4)+log_3(25)}`  (since `log_a(m*n)=log_am+log_an ` )

`=log_3(25)-log_3(4)-log_3(25)`

`=-log_3(4)`

`=-1.2619.`   (given)

Therefore, the answer is -1.2619.

Sources:

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aruv | High School Teacher | Valedictorian

Posted August 16, 2013 at 4:51 AM (Answer #2)

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`log_3 4=1.2619`

`log_3 .25=log_3 (25/100)`

`=log_3 (1/4)=log_3 4^(-1)=-1xxlog_3 4`

`=-1.2619` =-1.2619

because

`log_3(x/y)=log_3 x-log_3 y`

`log_3 x^m=mlog_3 x`  

`1/x^n=x^(-n)`

Answer is -1.2619

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