Question

Geometric Sequence

Answer 1

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Answer 2

@midhun.madhu1987

Answer 3

do you know the formula for G.P?

Answer 4

i am not sure @Mokeira

Answer 5

this is it
try and substitute then tell me if you get stuck...but try first

Answer 6

so \[S _{n}=20(1/4-1)/1/4-1\]

Answer 7

\[S _{n}=\frac{ a(r ^{n}-1) }{(r-1) }\]
where r>1
Our r is 1/4 so it is less than 1, therefore we use
\[S _{n}=\frac{ a(1-r ^{n}) }{( 1-r) }\]
when we substitute
\[\frac{ 20(1-\frac{ 1 }{ 4 }^{20}) }{1-\frac{ (1 }{4 }) }\]
can you be able to simplify that

Answer 8

do you cross out both 1/4

Answer 9

no....

Answer 10

can you help me simplify it because this is my first time doing this.

Answer 11

work out the numerator first then work out the denominator...do not think of crossing out anything..remember in the numerator only 1/4 is raised to the power 20