Interactive practice questions
In an arithmetic progression, $T_4=5.2$T4=5.2 and $T_{14}=9.2$T14=9.2.
By substituting $T_4=5.2$T4=5.2 into the equation $T_n=a+\left(n-1\right)d$Tn=a+(n−1)d, form an equation expressing $a$a in terms of $d$d.
By substituting $T_{14}=9.2$T14=9.2 into the equation $T_n=a+\left(n-1\right)d$Tn=a+(n−1)d, form another equation for $a$a in terms of $d$d.
Hence solve for the value of $d$d.
Hence solve for the value of $a$a.
Find $T_{26}$T26, the $26$26th term in the sequence.
What is the sum of the first $25$25 terms?
The sum of the terms of a sequence is:
Find the sum of the first $10$10 terms of the arithmetic sequence defined by $T_1=6$T1=6 and $T_{10}=3.5$T10=3.5.
Find the sum of the first $10$10 terms of the arithmetic sequence defined by $T_1=-8$T1=−8 and $T_{10}=-2.75$T10=−2.75.