1/5 ^m times 1/4^18 = 1/2(10)^35
what is m?
please help me, how do you find this?
GMAT Prep exponent help!
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in general to solve such equation we need to use logarithms!
1/5^m * 1/ 4^18 = 1/(2*10^35)
take natural logarithm of both sides to get
m(ln5)+18(ln4)=ln2+35ln10
m(ln5)=ln2+35ln10-18(ln4)
m=(ln2+35ln10-18ln4)/ln5
every decent calculator has a tool for calculating natural logarithms
evaluating the last expression yields m=35
might seem hard, but if the equation gets a bit less obvious its is way easier to just use logarithms.
BTW are we allowed to use some sort of calculator on the test ?
1/5^m * 1/ 4^18 = 1/(2*10^35)
take natural logarithm of both sides to get
m(ln5)+18(ln4)=ln2+35ln10
m(ln5)=ln2+35ln10-18(ln4)
m=(ln2+35ln10-18ln4)/ln5
every decent calculator has a tool for calculating natural logarithms
evaluating the last expression yields m=35
might seem hard, but if the equation gets a bit less obvious its is way easier to just use logarithms.
BTW are we allowed to use some sort of calculator on the test ?