The nth term of a G.P is 5^{1-n} find a and r.
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note that $\displaystyle 5^{1-n} = \frac{5}{5^n}$ so ... $\displaystyle ar^n = \frac{5}{5^n}$ can you dtermine $\displaystyle a$ and $\displaystyle r$ now?
thank you but U_{n} = ar^{n-1 }not ar^{n }and the answer is a =1 and r = 1/5
Originally Posted by wantanswers thank you but U_{n} = ar^{n-1 }not ar^{n }and the answer is a =1 and r = 1/5 depends on where you start n ... 0 or 1.
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