Page 36 - PRE-U STPM MATHEMATICS (T) TERM 1

Mathematics Term 1 STPM Chapter 2 Sequences and Series

12
12
12
12
=
+
(d) 1 2 1 2 1 2 1 12 – 7 2
+
7
4
4
12
12
+
= 1 2 1 2
5
4
13
= 1 2
5
= 13!
8! 5!
= 13 × 12 × 11 × 10 × 9 × 8!
8! × 5 × 4 × 3 × 2 × 1
= 1287
2
Exercise 2.6
1. Evaluate
(a) 5! (b) 8! (c) 10! (d) 8!
5!
(e) 10! (f) 18! (g) 20! (h) 16!
7! 15! 17! 4! 10! 6!
(i) 9! (j) 10!
2! 3! 4! (5!)

2. Rewrite in factorial form
(a) 10 × 9 × 8 (b) 12 × 11
(c) 22 × 21 × 20 (d) 18 × 17 × 16
5 × 4 × 3
(e) 21 × 20 × 19 (f) n(n – 1)(n – 2)
8 × 7 × 6
(g) (n + 2)(n + 1)n(n – 1) (h) (2n + 5)(2n + 4)(2n + 3)
(i) n(n – 1)(n – 2) (j) (n – 5)(n – 6)(n – 7)(n – 8)
3 × 2 × 1 5 × 4 × 3
3. Factorise
(a) 10! + 9! (b) 2(8!) – 7!
(c) 3(7!) + 4(9!) (d) (n + 1)! + n!
2
(e) (n + 1)! – (n – 1)! (f) n (n + 1)! + 2n(n!)
(g) (n + 1)! + n! + (n – 1)! (h) 8! + 7!
4! 5! 3! 2!
(i) 10! – 8! + 7! (j) n! + (n – 1)!
7! 3! 5! 4! 3! 2! r! (r + 1)!

4. Evaluate
8
15
10
20
(a) 1 2 (b) 1 2 (c) 1 2 (d) 1 2
0
17
4
3
8
10
8
5
6
13
5
12
÷
(e) 1 21 2 (f) 1 21 2 (g) 1 2 1 2 (h) 1 2 1 2
÷
3
4
3
4
2
2
3
5
10
16
9
16
–
+
(i) 1 2 1 2 (j) 1 2 1 2
5
4
4
12
123
02 STPM Math T T1.indd 123 3/28/18 4:21 PM