Ask your own question, for FREE!
Mathematics 13 Online
OpenStudy (anonymous):

30+5i / 30-5i

OpenStudy (asnaseer):

multiply the numerator and denominator by the complex conjugate of the denominator. that will turn the denominator into a real number.

OpenStudy (asnaseer):

does it make sense or do you need more explanation?

OpenStudy (anonymous):

900+10i+25i(squared) over 900+25i(squared)?

OpenStudy (asnaseer):

\[\frac{30+5i}{30-5i}=\frac{30+5i}{30-5i}*\frac{30+5i}{30+5i}=\frac{(30+5i)(30+5i)}{30^2+5^2}\]

OpenStudy (asnaseer):

remember:\[(a-bi)(a+bi)=a^2-b^2i^2=a^2-b^2(-1)=a^2+b^2\]

OpenStudy (anonymous):

OK, this whole (i) thing is confusing to me. I always forget to use the one when I multiply. thank you

OpenStudy (asnaseer):

yw - you just need practice - I'm sure you'll get the hang of these soon :)

OpenStudy (anonymous):

30 + ((5 * i) / 30) - (5 * i) = 30 - 4.833333

OpenStudy (anonymous):

Squareroot of -15 times Squareroot of -15

OpenStudy (anonymous):

anymore?

OpenStudy (anonymous):

15i ?

OpenStudy (anonymous):

yes

OpenStudy (anonymous):

if im wrong idk what i did wrong

OpenStudy (asnaseer):

\[\begin{align} \frac{30+5i}{30-5i}&=\frac{30+5i}{30-5i}*\frac{30+5i}{30+5i}=\frac{(30+5i)(30+5i)}{30^2+5^2}\\ &=\frac{30^2+2*30*5i+(5i)^2}{900+25}\\ &=\frac{900+300i+(25i^2)}{900+25}\\ &=\frac{900+300i+(25*(-1))}{925}\\ &=\frac{900+300i-25}{925}\\ &=\frac{875+300i}{925}\\ &=\frac{35+12i}{37}\\ \end{align}\]

Can't find your answer? Make a FREE account and ask your own questions, OR help others and earn volunteer hours!

Join our real-time social learning platform and learn together with your friends!
Can't find your answer? Make a FREE account and ask your own questions, OR help others and earn volunteer hours!

Join our real-time social learning platform and learn together with your friends!