The sum of the first $20$ terms of an arithmetic sequence is $65$. The sum of the next $8$ ter

Question

The sum of the first $20$ terms of an arithmetic sequence is $65$. The sum of the next $8$ terms is $-30$. Find the first term and the common difference of this sequence. [3] A sequence has $n$th term given by $u_n=e^{k(n+1)}$, where $k$ is a constant and $k\ne 0$. Show that this sequence is geometric. [2]

Accepted Answer

(a) First term $8$; common difference $-\dfrac12$ (b) Common ratio $e^k$

N2025 P1 Q2

N2025 P1 Q2

Video Solution:

Solution 1