1.Sa se determine x,y apartin R astfel incat sa aiba loc egalitatile de numere:
a) 4+x+(5y-x)i=3y-1+(7+2x)i
b)2x+yi+3i(x+4y)=2+4i
2.Sa se efectueze:
a)(3-4i)-(6-8i)
b)(2-i)(2+i)
3.Sa se calculeze |z|,-z,1/z stiind ca:
a)z=-2+3i
b)z=(2+3i)(1-i)+i-3
c)z=(i-1)(1+2i)-3(2-i)
a)desfaci parantezele si grupezi termenii reali deoparte si termenii imaginari deoparte
Se formeaza sistemul de 2 ecuatii
x-3y=-5
3x+5y=7 solutii x=1,y=-2
b) in mod asemanator2x+(3x+13yi=2+4i
faci sistem
x=2
3x+13y=4
solutii x=1, y=1/13
Ex2
b)(2-i)*(2+i)=4-i^2= 4+1=5
Ex 3
lzl=radical(-2)^2+3^2=rad13
Fie1/z=a+bi sestie ca z*1/z=1
Deci
(-2+3i)*(a+bi)=1
Efectuezi calculele si ajungi la (-2a_3b)+i*(3a-2b)=1
faci sistemul
-2a-3b=1
3a-2b=0 si-l rezolvi
-z=-(-2+3i)=2-3i
analog rexolvi si celalte exercitii