Evaluate
\frac{9}{20}-\frac{3}{20}i=0.45-0.15i
Real Part
\frac{9}{20} = 0.45
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\frac{3\left(6-2i\right)}{\left(6+2i\right)\left(6-2i\right)}
Multiply both numerator and denominator by the complex conjugate of the denominator, 6-2i.
\frac{3\left(6-2i\right)}{6^{2}-2^{2}i^{2}}
Multiplication can be transformed into difference of squares using the rule: \left(a-b\right)\left(a+b\right)=a^{2}-b^{2}.
\frac{3\left(6-2i\right)}{40}
By definition, i^{2} is -1. Calculate the denominator.
\frac{3\times 6+3\times \left(-2i\right)}{40}
Multiply 3 times 6-2i.
\frac{18-6i}{40}
Do the multiplications in 3\times 6+3\times \left(-2i\right).
\frac{9}{20}-\frac{3}{20}i
Divide 18-6i by 40 to get \frac{9}{20}-\frac{3}{20}i.
Re(\frac{3\left(6-2i\right)}{\left(6+2i\right)\left(6-2i\right)})
Multiply both numerator and denominator of \frac{3}{6+2i} by the complex conjugate of the denominator, 6-2i.
Re(\frac{3\left(6-2i\right)}{6^{2}-2^{2}i^{2}})
Multiplication can be transformed into difference of squares using the rule: \left(a-b\right)\left(a+b\right)=a^{2}-b^{2}.
Re(\frac{3\left(6-2i\right)}{40})
By definition, i^{2} is -1. Calculate the denominator.
Re(\frac{3\times 6+3\times \left(-2i\right)}{40})
Multiply 3 times 6-2i.
Re(\frac{18-6i}{40})
Do the multiplications in 3\times 6+3\times \left(-2i\right).
Re(\frac{9}{20}-\frac{3}{20}i)
Divide 18-6i by 40 to get \frac{9}{20}-\frac{3}{20}i.
\frac{9}{20}
The real part of \frac{9}{20}-\frac{3}{20}i is \frac{9}{20}.
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