Questions on Algebra: Complex Numbers answered by real tutors!

Tutors Answer Your Questions about Complex Numbers (FREE)

Question 202880: The sum of two complex numbers is 6 and their product is 10. One number is?
a. -3+i
b. -3-i
c. 3+i
d. -6+i
Click here to see answer by dyakobovitch(40)

Question 202835: The equation of a polynomial with real coefficients that has the roots 2 and 3(imaginary i) is?
a. x^3-2x^2+9x-18
b. x^3-2x^2-12x-18
c. x^3+2x^2-9x-18
d. x^3-2x^2+9x-20
Click here to see answer by jsmallt9(3296)

Question 203100: Imaginary numbers

x^2-2x+12,x=1-2i
Click here to see answer by jim_thompson5910(28476)

Question 203174: what is the value of the expression 2x to the second power + 3xy - 4y to the second power when x=2 and y= -4 please explain
Click here to see answer by rfer(12644)

Question 203271: i want the integral of dx/(2+sinx)
Click here to see answer by jsmallt9(3296)

Question 203257: Please walk me thru how answer is gotten. they say the answer is x-13/(x+3)(x-3). I am mainly interested in how to arrive at the numerator: (x-13)
Click here to see answer by jsmallt9(3296)

Question 203358: HI. This expression is suppose to wrote in a + bi form. I am having some trouble solving it. It's 5i^3/2(square root -4). Thank you very much.
Click here to see answer by ankor@dixie-net.com(15622)

Question 203663: I dont understand why its necessary to write a complex number in a+bi form.
Click here to see answer by Alan3354(30945)

Question 203781: (z-10)(z+10)=z^2-100
Click here to see answer by Alan3354(30945)

Question 203781: (z-10)(z+10)=z^2-100
Click here to see answer by stanbon(57214)

Question 203990: Could you help me to understand the complex numbers formulas and specially their signs?
Do I must commit all to memory or there are some correspondences between them? I compared some of mine with some of solved ones here but they were absolutly different with my formulas!!!
I have (a+bi).(c+di)=(ac-bd).(ad+bc)i [why both sides are multiplay and why we have minus in the other side?!]
and what's the other side of (a+bi).(c-di)=?
cause I have :

about the denominator I have (a+bi).(a-bi)=a^2 + b^2
but there is a solved example in this site against my lecture note's formula and its examples:
Question 202104: (5 -i)(5 +i)= 5^2 - i^2

Click here to see answer by ptaylor(2048)

Question 204916: Q.1. Find the fourth roots of -1.
Q.2. If 3/(2+cosx + isinx )=a+ib,then prove that a.a+b.b =4a-3.
Click here to see answer by stanbon(57214)

Question 205256: Given z=5+3i and w=7-4i find zw
Click here to see answer by solver91311(16868)

Question 205400: 3 + 3i divided by 3 - 4i
Click here to see answer by Alan3354(30945)

Question 205598: If we write the following complex number in standard form:
(sqrt7 + sqrt11 i)(sqrt7 - sqrt11 i) = a + bi
Then a = ? and b = ?
Click here to see answer by stanbon(57214)

Question 205743: find all solutions of the equation z^2 = -6 + 8i
Click here to see answer by stanbon(57214)

Question 205836: simplify the expression:
(3n+2)!/(3n-2)!
Click here to see answer by stanbon(57214)

Question 205835: Find all the values of the following (separate multiple answers with commas):
1. (-256)^1/4 = ?
2. 1^1/5 = ?
3. i^1/4

Click here to see answer by Alan3354(30945)

Question 205835: Find all the values of the following (separate multiple answers with commas):
1. (-256)^1/4 = ?
2. 1^1/5 = ?
3. i^1/4

Click here to see answer by stanbon(57214)

Question 206278: Find the slope of the line that passes through the points (6,5) and (6,-1)
Click here to see answer by Alan3354(30945)

Question 207197: I HAVE A FINAL EXAM COMING UP AND I STILL DON'T UNDERSTAND COMPLEX NUMBERS. THE DIRECTIONS ARE: PUT EACH NUMBER IN THE STANDARD COMPLEX FORM OF A+Bi.
THE PROBLEMS ARE:
1. 4-5 square root of -6
2. 3+ the square root of -7

Click here to see answer by Alan3354(30945)

Question 207349: The lenght
Click here to see answer by Alan3354(30945)

Question 207423: Hi there... i just have a few questions that i would like to ask regarding complex numbers.
1)
i would show you how much i can do on this one... however, im completely stuck sorry
and i was unable to find a proper square root sign, so hope that its alright.

2)
I REALLY strggle with De Moivre's theorem.
for this question i have to find the following:
a)
b)find when
c)write in polar form
d}find or using De Moivre's theorem.
SO those are all my questions, hope they are alright
Thanks
Christelle :D
Click here to see answer by Edwin McCravy(8879)

Question 207549: Expand: (2+3i)^2
Click here to see answer by jim_thompson5910(28476)

Question 207791: 2
_______
3-i
Click here to see answer by jim_thompson5910(28476)

Question 208391: How do I simplify (-5)cubed(-1/5)squared
Click here to see answer by rfer(12644)

Question 208350: It says to write each quotient in the form of a + bi
Don't know how
The problem is 3i/-2+i
Click here to see answer by Edwin McCravy(8879)

Question 208479: i need help with this problem (y-4)squared=2y
Click here to see answer by stanbon(57214)

Question 207869: Given: Neither a nor b equal zero.
Evaluate:
(a+bi)[(a/a^2+b^2)-(b/a^2+b^2)i]
Click here to see answer by stanbon(57214)

Question 208606: A technician experimentally determined the boiling point of octane to be 124.1 degrees celsius. The actual boiling point of octane is 125.7 degrees celsius. Calculate the error and the percent error.

thank you
Click here to see answer by rfer(12644)

Question 209218: 3 - 6i
------ > Divided By
6 + 4i
Click here to see answer by stanbon(57214)

Question 208940: 12h^2 - 6h + 6h^2 - 2h
Click here to see answer by RAY100(1637)

Question 208574: there are three problems i need help
2+i=
3+2i+2+i=
5+2i.3+i=
Click here to see answer by Alan3354(30945)

Question 210337: Solve for x^2 + 61 =12x answer must be in form a+bi
Click here to see answer by ankor@dixie-net.com(15622)

Question 210457: how do you write the expression -2+4i/6+3i as a complex number in standard form?
Click here to see answer by solver91311(16868)

Question 210454: How do you write the expression (-6-29i)+(8-12i) as a complex number in standard form?
Click here to see answer by Earlsdon(6287)

Question 210455: how do you write the expression 2i(5+i)(-2+7i) as a complex number in standard form?
Click here to see answer by stanbon(57214)

Question 211101: Hi I need help with these questions:
1. -9+i/-9-3i I divided the num and dem by the recip -9+3i and then used FOIL is that correct then simplified My answer was 13/15-3i/15 help
2. x^-6x+17=0 Do I use the quadr formula to solve this I did and got 4-i and 4+i
3. (x^+3x)+5=0 help my ans were not close to the choices I had (also noted is problem that I=sqrt of 1)
4. (x^-2x)+7=0 help my ans were not close to the choices I had (also noted is problem that I=sqrt of 1)
5. (x^+2x)+7=0 help my ans were not close to the choices I had (also noted is problem that I=sqrt of 1)

Click here to see answer by jim_thompson5910(28476)

Question 211188: How does one determine the number of roots of unity? The solution for the following problems must be made using the radian not polar rectangular approach:
(1-i)^1/4
(1+i*sqrt(3)^7/2
(-i)^1/2
These problems I have to work are not from my text, but rather from the instructor. My textbook is:
Tristan Needham's - Visual Complex Analysis ISBN 978 0 19 853446 4 (pbk)
Click here to see answer by stanbon(57214)

Question 211347: Divide: 8/9i
Click here to see answer by stanbon(57214)

Question 211347: Divide: 8/9i
Click here to see answer by Alan3354(30945)

Question 211373: -(6-2^3-3)^2 + 2 x (-4)
Evaluate
Click here to see answer by rapaljer(4667)

Question 211377: -4(-6t - u) + 4 (2u + 6t)
Click here to see answer by rapaljer(4667)

Question 211378: ( x^4)^2
----
-2y^2
Sorry if it's not easy to understand. The problmer is a fraction within parentheses the only number outside the parenthesis is the 2 exponent. I am to simplify without the parenthesis. Thanks in advance
Click here to see answer by rapaljer(4667)

Question 211382: I need to solve for B
S = 2B + Ph
where B is the area of the base, P is the perimeter of the base and h is the heigth of the prism.
Click here to see answer by rapaljer(4667)

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