Question #27e2b

3 Answers
Feb 5, 2018

#z_1/z_2=2+i#

Explanation:

We need to calculate
#z_1/z_2=(4-3i)/(1-2i)#

We can't really do much because the denominator has two terms in it, but there is a trick we can use. If we multiply the top and bottom by the conjugate, we'll get an entirely real number on the bottom, which will let us calculate the fraction.

#(4-3i)/(1-2i)=((4-3i)(1+2i))/((1-2i)(1+2i))=(4+8i-3i+6)/(1+4)=#

#=(10+5i)/5=2+i#

So, our answer is #2+i#

Feb 5, 2018

The answer is #=2+i#

Explanation:

The complex numbers are

#z_1=4-3i#

#z_2=1-2i#

#z_1/z_2=(4-3i)/(1-2i)#

#i^2=-1#

Multiply the numerator and denominator by the conjugate of the denominator

#z_1/z_2=(z_1*barz_2)/(z_2*barz_2)=((4-3i)(1+2i))/((1-2i)(1+2i))#

#=(4+5i-6i^2)/(1-4i^2)#

#=(10+5i)/(5)#

#=2+i#

Feb 5, 2018

#2+i#

Explanation:

#z_1/z_2=(4-3i)/(1-2i)#

#"multiply numerator/denominator by the "color(blue)"complex conjugate"" of the denominator"#

#"the conjugate of "1-2i" is "1color(red)(+)2i#

#color(orange)"Reminder"color(white)(x)i^2=(sqrt(-1))^2=-1#

#rArr((4-3i)(1+2i))/((1-2i)(1+2i))#

#"expand factors using FOIL"#

#=(4+5i-6i^2)/(1-4i^2)#

#=(10+5i)/5=2+i#