Monday

April 21, 2014

April 21, 2014

Posted by **Tara** on Thursday, August 16, 2012 at 12:08pm.

Can someone tell me if I'm correct?

1.(2+4i / 3-i)

= 6/7+5/7i

- Algebra2 -
**bobpursley**, Thursday, August 16, 2012 at 12:21pm2+41 /(3-i)

rationalize

(2+4i)(3+i)/10= (6+2i+12i-4)/10=

=(2+14i)/10

- Algebra2 -
**Tara**, Thursday, August 16, 2012 at 12:31pmAhh!

I'm confused about this math stuff:/

it's my first time trying these algebra problems.

I'm trying to go by the teacher's examples.

Can You tell me if these are right:p?

2. (7-√-15)^2

= 34+14i√15i

3.4+√-20 / 2

=2+2.5√4i

- Algebra2 -
**bobpursley**, Thursday, August 16, 2012 at 12:32pmanother way, in polar form:

(2+4i)=sqrt20@arctan2

(3-i)=sqrt10@arctan(-1/3)

so (2+4i)/(3-i)=sqrt20/sqrt10 @ (arctan2-arctan-1/3)=sqrt2 @(1.11rad-(-.321))

= sqrt2 @1.43rad=sqrt2 @ 81.9 deg

Now converting this (only to compare with the above)

= sqrt2 (cos81.9+isin81.9)

= (.198+i*1.40)

and the above is .2+i1.40

I rounded the angles on the arctan conversions...

- Algebra2 -
**bobpursley**, Thursday, August 16, 2012 at 12:37pm2. (7-√-15)^2

= 34+14i√15i ????

(7-isqrt15)^2=49-15-2isqrt15=34-2i sqrt15

3.4+√-20 / 2

=2+2.5√4i ????

4/2+1/2 i sqrt20=2+.5i*sqrt4*sqrt5

= 2+i sqrt5

- Algebra2 -
**Steve**, Thursday, August 16, 2012 at 1:16pm(7-isqrt15)^2=49-15-2isqrt15??

I get 49-15- 14√15 i

**Related Questions**

Algebra2/Trig - sqr(x^2-4)+(x^2)/x^2+1 I got ((x^2+1)*sqr(x^2-4)+x^2)/x^2+1 But ...

Algebra2 - i was wondering if someone could check the answer i got for this math...

math - In my math book i got a question that said 1/7 times 1/7. I got answer of...

algebra2 - How do i enter my answer? so the question is Simplify: √3:(63x^...

math - (3 + 2(8 + 5 • 2 ÷ 4) – 9) what is the correct answer to this problem I ...

Math - Could you help me with this problem? -2 5 Sorry couldn't type the problem...

algebra - the equation is : - (2x + 3)-(4 + x). Using the distributive property...

Math 141 - I am having trouble with this problem. perform the indicated ...

algebra2 - Write the expression (2x)(4y) + 9x + 10y + (8x)(4y) in a simpler form...

Algebra - Use the formula C=2pi to find the radius, r, for a circle with a ...