series/log HELP (1 Viewer)

[A Leaf]

^^^^(the question is attached here)

so I was good with this question up until the point where I'm logging both sides to get the value of n for iii)
what I did was log(500000)/log(105000) but that gives about 1.35 which is obviously wrong and the answer says i was meant to simplify 500000/105000 first which is 5/1.05 and then do log(5)/log(1.05) which gives me the correct answer 32.92
I was just wondering - why? Like why did I have to simplify first?

 

[HeroWise]

Feel so dumb... I spent 2 mins figuring if It was super or time repayments ARGHHAHSHSH and then in second part, i forgot to take the minus while multiiplying and got a negative 500000 instead of positive
Enough of my rant and
Back to your question



no cluee ..... ;-;

 

[fan96]

Where did the come from?

Also, if you happened to do this, note that

 

[HeroWise]

I think he meant that taking logs without simplifying from both sides dont produce 32.92?

 

[supR]

Maybe you typed it wrong in your calculator?
Idk my friend does that alot and tells me the answer is wrong.


Sent from my iPhone using Tapatalk

 

[A Leaf]

ooooooooooooooooooh I get so what I did wrong was not realise that 100,000 x 1.05^n is not the same as (100,000 x 1.05)^n so I think that's why I got the wrong answer it was basically me using the wrong values

 

[A Leaf]

BTW thanks guys, I appreciate the massive help