Find the sum of the geometric sequence. (3/2),(3/8),(3/32),(3/128),(3/512) PLEASE HELP ! I GIVE MEDALS
Just add up the fractions... Or terms.
THats not the answer
@amoodarya and ideas ?
s=3/2+3/8+3/32+3/128 +3/512 +... miltiply by 1/4 (r=1/4) 1/4s= 3/8+3/32+3/128 +3/512 +... now s-1/4s=3/2 so 3/4s=3/2
I dont see that ..... these are the options @amoodarya
What did I say? Add up the fractions! That's the sum! the final result after adding is the sum! So the answer is C.
what about Write the sum using summation notation, assuming the suggested pattern continues. 16 + 25 + 36 + 49 + ... + n2 + ... @Zelda
1^2+2^2+3^2+.....n^2=n(n+1)(2n+1)/6 so 4^2+5^2+6^2+....n^2=1^2+2^2+3^2+.....n^2-(1+4+9)=n(n+1)(2n+1)/6-(1+4+9)
so which option ? @amoodarya
and for which question ?
s=3/2+3/8+3/32+3/128 +3/512 s=3/512(256+64+16+4+1) s=1023/512
can you help me with that second one i just commented
@amoodarya
second question did you mean 4^2+5^2+...n^2= ? or 4^2+5^2+...n^2+....= ?
the second one @amoodarya
yeah the second question
4^2+5^2+...n^2+....= @amoodarya
for this question 16 + 25 + 36 + 49 + ... + n2 + ...
1^2+2^2+3^2+.....n^2+... =infinity but 1^2+2^2+3^2+.....n^2=n(n+1)(2n+1)/6 so 4^2+5^2+6^2+....n^2=1^2+2^2+3^2+.....n^2- (1+4+9)=n(n+1)(2n+1)/6- (1+4+9)
The options are Im just having a hard time reading that
@amoodarya
D.
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