<p>hey guys
so i've been trying to understand this math problem that was in my math workout princeton review book but their explanation didnt really help me..
please help :)</p>
<p>9.) If f(1)=5 and f(n+1)=2(f(n))-6, what is the value of f(3)?
answer choices
a.) -2
b.) 2
c.) 4
d.) 6
e.) 15</p>
<p>i know what the answer is but i DON'T know why
please help!! i cant sleep until someone figures this out.</p>
<p>This is probably just repeating what's in your book, but here goes.
f(2) = 2(f(1)) - 6 = 2<em>5 - 6 = 4.
f(3) = 2(f(2)) - 6 = 2</em>4 - 6 = 2. So the answer is b. Now, I hope you can sleep.</p>
<p>haha yeah thanks that was from my book
can you tell me why you used f(2) and f(3) ?
thanks :)</p>
<p>yeah i dont understand this problem as well</p>
<p>I GOT IT!! well in order to find f(3) u must first begin with f(2) now f(2)=f(1)+f(1) so now that u have that u can easily identify that f(2)=2(f(1))-6 which is f(2)=2*5-6 which is equal to 4 so f(2)=4</p>
<p>now that we have f(2) we can now say that f(2+1)=f(3) so f(3)=2f(2)-6 which is the same as saying f(3)=2*4-6 which is 2</p>
<p>f(3)=2</p>
<p>i thought that greennblue's explanation was as simple as it gets. if you can't understand it, then who else can explain it</p>
<p>i had to break it down its all good.. we all have moments where something just dosen't click</p>
<p>its the way of ETS</p>
<p>If f(1)=5 and f(n+1)=2(f(n))-6, what is the value of f(3)?</p>
<p>f(2) = 2<em>f(1) - 6 = 4
f(3) = 2</em>f(2) - 6 = 2</p>
<p>therefore the answer is (b)</p>
<p>yeah someone has already come up with that same solution</p>