C2 geometric sequences- least value of n
" Find the least value of n such that the sum 3+6+12+24+... to n terms would first exceed 1.5 million"
This is my working attached and my answer is slightly different to that of the book's. (The book's answer is my last line of working). The answer I got to was 19.93. Can someone tell me where I went wrong?
This is my working attached and my answer is slightly different to that of the book's. (The book's answer is my last line of working). The answer I got to was 19.93. Can someone tell me where I went wrong?
Original post by jessyjellytot14
Can someone tell me where I went wrong?
there should be a fullstop after million
Original post by username..1111
there should be a fullstop after million
Will I get the right answer if I put a full stop after million?
Spoiler
Original post by jessyjellytot14
" Find the least value of n such that the sum 3+6+12+24+... to n terms would first exceed 1.5 million"
This is my working attached and my answer is slightly different to that of the book's. (The book's answer is my last line of working). The answer I got to was 19.93. Can someone tell me where I went wrong?
This is my working attached and my answer is slightly different to that of the book's. (The book's answer is my last line of working). The answer I got to was 19.93. Can someone tell me where I went wrong?
The sum, not the term
Original post by TeeEm
am I too late?
yup , i was 22 mins too late ;(
Original post by Naruke
The sum, not the term
Original post by the bear
it is a GP with a = 3 & r = 2
Sn = {a ( 1 - r n )} / ( 1 - r ) > 1500000
put in the values for a, r & find n. you may need logarithms ?
Sn = {a ( 1 - r n )} / ( 1 - r ) > 1500000
put in the values for a, r & find n. you may need logarithms ?
Ohhh okay it makes sense now
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