Posted by Tara on Thursday, August 16, 2012 at 12:08pm.
2+41 /(3-i)
rationalize
(2+4i)(3+i)/10= (6+2i+12i-4)/10=
=(2+14i)/10
Ahh!
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
another 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...
2. (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
(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 ...
math - Generalize this to fine a formula for the integral: sin(ax)cos(bx)dx ...
algebra - will someone tell me what the answer is to this problem? and how they ...
Algebra2 - i was wondering if someone could check the answer i got for this math...
Math - Hi, would someone mind just checking the answer I got for this formula ...
trig - Write the expression and evaluate. There is only one answer whIch should ...
Trig - Find cos(s+t) if cos s= -1/2 and sin t= 3/5, s and t are in quadrant II. ...
Math - Can someone tell me how they got the answer. Problem: 9^(x+6)=7x My ...
Physics - I thought I did the problem right, but I don't think I came out ...
Math - When I did the following problem, I got -12 as my answer. It is an ...
For Further Reading
