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Find the missing terms in the geometric sequence.

 

-4, _, _, _, _, -12500.

 Jun 3, 2021
 #1
avatar+121054 
+1

We  can solve this for the common ratio , r

 

-4 (r)^5  =   -12500      divide both sides  by   -4

 

r^5  =  3125   take the  5th root of both sides

 

r   =  5

 

So  the missing terms are

 

-20   -100     -500    -2500  

 

 

cool cool cool

 Jun 4, 2021
 #2
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+1

I got r = 625 because I multiplied 1/5 times both sides. That was what I was taught but it didn't seem right. Shouldn't performing the square root and multiplying by 1/5 give me the same answer?

Guest Jun 4, 2021
 #3
avatar+121054 
+1

We are not  taking  3125 * (1/5)

 

We  are  taking  the fifth root  of 3125 =     (3125)^(1/5)    =   5    =   r

 

This is because   5*5*5*5*5   =  3125

 

Does that  make sense   ???

 

 

cool cool cool

CPhill  Jun 4, 2021
 #4
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+1

MY BAD! I was doing it all wrong. It was the exponent of 1/5 because I was multiplying it by the exponent of 5. Thank you! I figured it out.

Guest Jun 4, 2021

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