- Home
- Standard 11
- Mathematics
4-1.Complex numbers
easy
यदि $z$ एक सम्मिश्र संख्या हो, तो $(\overline {{z^{ - 1}}} )(\overline z ) = $
A
$1$
B
$-1$
C
$0$
D
इनमें से कोई नहीं
Solution
(a) माना $z = x + iy,\overline z = x – iy$ एवं ${z^{ – 1}} = \frac{1}{{x + iy}}$
$⇒ (\overline {{z^{ – 1}}} ) = \frac{{x + iy}}{{{x^2} + {y^2}}}$;
$\therefore $$(\overline {{z^{ – 1}}} )\,\bar z = \frac{{x + iy}}{{{x^2} + {y^2}}}(x – iy) = 1$
Standard 11
Mathematics