How do you solve log_b(2) = .105logb(2)=.105?

1 Answer
Dec 24, 2015

The trick here would be to convert the log function to exponent form and then solve. Please check the explanation for two approaches to solve the same.

Explanation:

log_b(2) = 0.105logb(2)=0.105

The rule
log_b(a) = k => a=b^klogb(a)=ka=bk

Using this rule we get

2 = b^0.1052=b0.105

We can solve this by taking 0.1050.105 root of 22

2^(1/0.105) = b210.105=b

b =736.12630909184909714688332138981b=736.12630909184909714688332138981 using calculator.

Alternate Method

log_b(2) = 0.105logb(2)=0.105
Using change of base rule which says log_b(a) = log(a)/log(b)logb(a)=log(a)log(b)
We get log(2)/log(b) = 0.105log(2)log(b)=0.105
Cross multiplying we get log(2) = 0.105*log(b)log(2)=0.105log(b)
log(2)/0.105 = log(b)log(2)0.105=log(b)
2.8669523396569637639403704259476 = log(b)2.8669523396569637639403704259476=log(b)
#b = 10^2.8669523396569637639403704259476

b=736.12630909184909714688332138989b=736.12630909184909714688332138989

We can round it as per requirement or instructions.