How do you simplify [sqrt2(cos((7pi)/4)+isin((7pi)/4))]div[sqrt2/2(cos((3pi)/4)+isin((3pi)/4))][2(cos(7π4)+isin(7π4))]÷[22(cos(3π4)+isin(3π4))] and express the result in rectangular form?

2 Answers
Apr 21, 2018

[sqrt2(cos((7pi)/4)+isin((7pi)/4))]div[sqrt2/2(cos((3pi)/4)+isin((3pi)/4))][2(cos(7π4)+isin(7π4))]÷[22(cos(3π4)+isin(3π4))]

=[sqrt2(cos((7pi)/4)+isin((7pi)/4))]/[sqrt2/2(cos((3pi)/4)+isin((3pi)/4))]=2(cos(7π4)+isin(7π4))22(cos(3π4)+isin(3π4))

=[2(cos((7pi)/4)+isin((7pi)/4))]/[(cos((3pi)/4)+isin((3pi)/4))]=2(cos(7π4)+isin(7π4))(cos(3π4)+isin(3π4))

=[2e^(i(7pi)/4)]/[e^(i(3pi)/4)]=2ei7π4ei3π4

=2e^(i((7pi)/4-(3pi)/4)]=2ei(7π43π4)

=2e^(ipi)=2eiπ

=2(cospi+isinpi)=2(cosπ+isinπ)

=2(-1+i*0)=-2+i*0=2(1+i0)=2+i0

Apr 21, 2018

The answer is -2+0i2+0i

Explanation:

Two divide two complex numbers, we divide their moduli and subtract their arguments.

So our number will have modulus

sqrt2/(sqrt2/2)=1/(1/2)=2222=112=2

and argument of

7/4pi-3/4pi=4/4pi=pi74π34π=44π=π

So our number will be

2(cospi+isinpi)=2(-1+0i)=-2+0i2(cosπ+isinπ)=2(1+0i)=2+0i