Sequences & Series  Arithmetic  the General term.
Test Yourself 2  Solutions.
Answer. T1 = 2 and d = 3.
Finding a term  1. The arithmetic sequence 7, 11 and 15:
So T_{1} = 7 and d = 4. For 111 to be a member of this sequence: 111 = 7 + (n1)×4 108 = 4n n = 27 which is an integer. ∴ 111 is a member of the sequence. 
2. Series is 84, 78 and 72
So T_{1} = 84 and d = 6 ∴36 = 84 + (n  1)(6) 6n = 126
So 36 is part of the series and is the 21st term. 
3. S_{n} = 25n  2n^{2}.


Finding a 1^{st} term  4.  5. 
Finding a difference.  6. 
7. 
Finding the number of terms  10. (i) Sum of interior angles = (n  2)×180° (ii) T1 = 120° and d = 5°. 

11.  12.  
Given 2 terms  13.  14. 
15.  
Miscellaneous.  17.  
18.  
19.  20. 