Question

how do you evaluate this on your calculator
log(4)23

but the 4 is lower than the word log

Answer 1

\[\frac{ln(23)}{ln(4)}\]

Answer 2

\[log_b(x)=\frac{log_a(x)}{log_a(b)}\]

Answer 3

yeh remembering the formula is for people that dont know what they are doing though

Answer 4

but you only have two logs on your calculator,
\[\log=\log_{10}\] and \[\ln=\log_e\]

Answer 5

i disagree. if i want to solve for example
\[2^x = 1000\] for x the only way to do it is to compute
\[\frac{\ln(1000)}{\ln(2)}\]

Answer 6

because i have no way of knowing what
\[\log_2(1000)\] is

Answer 7

so without the change of base formula i am lost. it is how you solve an equation when the variable is in the exponent

Answer 8

yeh but you derive the eqn, you dont memroise it

Answer 9

maths is alot easy to learn derivations than to memorise eqns

Answer 10

so how wuld i input this into my calc

Answer 11

no i just know that
\[A = b^x \] same as \[x=\frac{ln(A)}{\ln(x)}\]

Answer 12

sorry i mean
\[A=b^x \] means \[x=\frac{\ln(A)}{\ln(x)}\]

Answer 13

lols :P

Answer 14

damn
\[A=b^x\] means \[x=\frac{\ln(A)}{\ln(b)}\]

Answer 15

that is the one i want!

Answer 16

:P

Answer 17

I just remember a basic proof

A= b^x

ln(A) = ln(b^x)
ln(A) = x ln(b)
x= ln(A) / ln(b)

Answer 18

i do not need to reinvent the wheel every time and say "take the log, pull out the exponent, and then solve " because it is always the same

Answer 19

takes 5seconds to derive, says me all the time smashing some formula into my head for no reason

Answer 20

ok we will have to agree to disagree. same reason i would never say
\[e^x = A\]
\[\ln(e^x)=\ln(A)\]\[x\ln(e)=\ln(A)\] \[x=\ln(A)\]

Answer 21

it is just how one solves for a variable in the exponent!

Answer 22

the meaning of \[b^x\] is \[e^{x\ln(b)}\] elsewise \[2^{\sqrt{3}}\] makes no sense

Answer 23

can someone atleast tell me waht the answer to the problem is

Answer 24

yes it is the first thing i wrote
\[x=\frac{\ln(23)}{\ln(4)}\]

Answer 25

lols, whatever u wanna do.

but thats partly the reason why so many people seems to struggle with maths, theythink that is all about remember formulas , and that there are so many formulas !

When all they really need is figure out what to remember and what not to remember lols . The more you can derive the less likely it is to make a mistake.

Maths is just about smart memorisation lol

Answer 26

the almighty "change of base" formula which is good to remember

Answer 27

how would i put ln into calc

Answer 28

depends on the calculator. in mine i would type
\[ln (23) \div ln (4)\]

Answer 29

make sure to close the parentheses about the 23

Answer 30

is there an ln key

Answer 31

yes there should be. what calculator are you using?

Answer 32

you dont know how to use a calculator ? :|

Answer 33

the teacher really dropped the ball somewhere lols

Answer 34

im using ti-84, perhaps i just cant find the key

Answer 35

fancy one!

Answer 36

on the left hand side between log and sto

Answer 37

neva mind i put on my glasses and found the key, thank u satellite for ur help w/o being rude

Answer 38

no problem btw you could also type in
\[log(23)\div log(4)\] and get the same answer

Answer 39

i get 2.26 rounded

Answer 40

me 2

Answer 41

yay! gnight!

Answer 42

u 2