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Science-Related Homework Help Mathematics Topic started by: #8 on Oct 20, 2012



Title: Evaluate the expression can solve?
Post by: #8 on Oct 20, 2012
Evaluate the expression and write the result in the form a + bi.
(2/3 + 12i)(1/2 + 25i)

Evaluate the expression and write the result in the form a + bi.
1/(2-5i) - 1/(6+6i)

thanks, any answer will be given points, you don't have to answer both,
but if you see to many people answering 1, then go for the other
and if you answer both of them correctly you get the 10 points
thanks for all your aswers but I'm still getting them wrong


Title: Evaluate the expression can solve?
Post by: ilibee on Oct 20, 2012
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Title: Evaluate the expression can solve?
Post by: tomtom1234 on Oct 20, 2012
i will do the first one only .. which can help you in solving the second one ..if you want to

(2/3 + 12i)(1/2 + 25i)

start by expanding the bracket

2/3 * 1/2 + 2/3 *25 i + 12i * 1/2 + 12 i * 25 i

= 3 + 50/3 i + 6i + 300 i^2

we know i^2 = -1 so putting the value

= 3 + 68/3 i -300

= 68/3 i - 297


Title: Evaluate the expression can solve?
Post by: Tonbon1221 on Oct 20, 2012
(2/3 + 12i)(1/2 + 25i) = 2/6+ 50/3i+6i+300i^2= 1/3+22 2/3 i+ 300i^2

1/(2-5i) - 1/(6+6i)= (6+6i- 2+5i)/ (2-5i)(6+6i)= (4+11i)/(12-18i-30i^2)