Question

I need some help with the letter d please

Answer 1

`\sf\\\textsf{We have the geometric sequence:}\\1,3,9,27,81,243,...6561\\\textsf{Here,}\\\textsf{First term}(a)=1\\\textsf{Common ratio(r)}=(second\ term(t_2))/(first\ term(t_1))=(3)/(1)=3\\\\\textsf{nth term}(t_n)=ar^(n-1)=3^(n-1)`

`\sf\\\textsf{Now, if we equate the nth term with the last number in the sequence, we get the}\\\textsf{number of terms. Here, 'n' is the number of terms in the sequence.}\\6561=3^(n-1)\\\textsf{or, }3^8=3^(n-1)\\\textsf{or, }n-1=8\\\textsf{or, }n=9\\\\\textsf{So there are 9 terms in the sequence.}`