Question:
If 23 1 30 1 11 1 i ii i = A + iB where i = -1 then what is A + B equal to?
If 23 1 30 1 11 1 i ii i = A + iB where i = -1 then what is A + B equal to?
Options:
- a) -10
- b) -6
- c) 0
- d) 6 Direction for Questions (41-43): Consider the following for the three (03) items that follow: Let p = sin 35°, q = sin 25° and r = sin(-95°).
- a) -10
- b) -6
- c) 0
- d) 6 Direction for Questions (41-43): Consider the following for the three (03) items that follow: Let p = sin 35°, q = sin 25° and r = sin(-95°).
correct answer : b)
Explanation:
23 1
30 1
11 1
+
—
— –
i
ii
i
= 2(i2 – 1) – (3 +i)(3 – i + i -1) +1(3 – i)(i + 1)
= 2(-1 – 1) – (3 + i) 2 + 3i – i2 + 3 – i
= – 4 – 6 – 2i + 3i + 1 + 3 – i
= – 6= – 6 + 0i = A + iB
\ A + B = – 6 + 0 = – 6
23 1
30 1
11 1
+
—
— –
i
ii
i
= 2(i2 – 1) – (3 +i)(3 – i + i -1) +1(3 – i)(i + 1)
= 2(-1 – 1) – (3 + i) 2 + 3i – i2 + 3 – i
= – 4 – 6 – 2i + 3i + 1 + 3 – i
= – 6= – 6 + 0i = A + iB
\ A + B = – 6 + 0 = – 6