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z1=2+3i z2=2-3i z1+z2= z1-z2= z1:z1=​

Răspuns :

z1=2+3i

z2=2-3i

  • z1+z2= 2+3i + 2-3i = 4

  • z1-z2= 2+3i - (2-3i) = 2+3i-2+3i = 6i

  • z1:z1=

[tex] = {}^{2 + 3i)}\frac{2 + 3i}{2 - 3i} = \frac{(2 + 3i) {}^{2} }{(2 + 3i)(2 - 3i)} = \\ \\ = \frac{2 {}^{2} + 2 \times 2 \times 3i + (3i) {}^{2} }{2 {}^{2} - (3i) {}^{2} } = \\ \\ = \frac{4 + 12i - 9}{4 - ( - 9)} = \frac{5 - 12i}{4 + 9} = \\ \\ = \frac{5 - 12i}{13} = \frac{5}{13} - \frac{12}{13} i[/tex]

IMPORTANT:

[tex] \boxed{\orange{ {i}^{2} = - 1}}[/tex]

(a+b)² = a² + 2ab + b²

(a+b)(a-b) = a²- b²