2 years ago

Automatic Zoom

Mathematics

1 answer:

Solnce55 [7]2 years ago

7 0

D! I’ve taken this

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Is 4/16 equivalent to 3/5

azamat

No, as if you reduce 4/16 it is 1/4, not 3/5, therefore they are not equivalent.

7 0

3 years ago

What is the 7th term of the geometric sequence where a1 = -625 and a2 = 125

kykrilka [37]

Since the sequence is geometric, there is some constant $r$ such that the sequence is recursively given by

$a_n=ra_{n-1}$

By this definition, you can recursively substitute into the right hand side the definition for $a_{n-1},a_{n-2},\ldots$ to find an explicit formula for the $n$ th term.

$a_n=ra_{n-1}=r^2a_{n-2}=r^3a_{n-3}=\cdots=r^{n-1}a_1=-625r^{n-1}$

You know the second term, which means you can find $r$ :

$a_2=-625r^{2-1}\implies125=-625r\implies r=-\dfrac15$

So, the 7th term of the sequence is

$a_7=-625\left(-\dfrac15\right)^{7-1}=-\dfrac1{25}$