b)
(2+i)• (i-2)_conjugat
=(2+i)(-i-2)= -2i -4 -i² -2i=
=-2i -4 -(-1)-2i = -4i -4 +1= -4i - 3
c) amplificăm fracția data cu 1+i✓3
[tex]| \frac{(1 + i \sqrt{3}) {}^{2} }{(1 + i)(1 -i )} | = |\frac{1 + 2i \sqrt{3} + {i}^{2} }{1 - {i}^{2} } | = \\ = |\frac{1 + 2i \sqrt{3} - 1 }{1 - ( - 1)}| = |\frac{ 2i \sqrt{3} }{1 + 1} | = | \frac{2i \sqrt{3} }{2} |= \\ = |i \sqrt{3}| [/tex]
|i✓3|=✓(1²+✓3²)=✓(1+3)=✓4=2
