Q. Divide the following complex numbers.5−3i25+19i
Multiply by conjugate: To divide complex numbers, we multiply the numerator and denominator by the conjugate of the denominator. The conjugate of (5−3i) is (5+3i).5−3i25+19i×5+3i5+3i
Multiply numerators and denominators: Now, we multiply the numerators together and the denominators together.Numerator: (25+19i)(5+3i)Denominator: (5−3i)(5+3i)
Multiply out the numerator: First, we'll multiply out the numerator using the distributive property (FOIL method).(25+19i)(5+3i)=25⋅5+25⋅3i+19i⋅5+19i⋅3i=125+75i+95i+57i2Since i2=−1, we replace 57i2 with −57.=125+75i+95i−57=125+170i−57=68+170i
Multiply out the denominator: Next, we'll multiply out the denominator.(5−3i)(5+3i)=5×5+5×3i−3i×5−3i×3i=25+15i−15i−9i2Since i2=−1, we replace −9i2 with 9.=25−9=16
Simplify numerator and denominator: Now we have the simplified numerator and denominator.Numerator: 68+170iDenominator: 16We divide both the real and imaginary parts of the numerator by the denominator.(68+170i)/16=68/16+(170/16)i=4.25+10.625i
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