(a)[3]
Determine the value of $d$.
(b)[5]
Let $S_{77}$ represent the sum of the first $77$ terms of the arithmetic progression. Let $G_{10}$ represent the sum of the first $10$ terms of the geometric progression. Calculate $S_{77} - G_{10}$.
Mathematics 9709 · AS & A Level · Series
Series — practice question
An arithmetic progression begins with first term $5$ and has common difference $d$, with $d > 0$. The second, fifth and eleventh terms of the arithmetic progression, in that order, are the first three terms of a geometric progression.