જો ${A_i} = \left[ {\begin{array}{*{20}{c}}{{a^i}}&{{b^i}}\\{{b^i}}&{{a^i}}\end{array}} \right]$ અને $|a|\, < 1,\,|b|\, < 1$, તો $\sum\limits_{i = 1}^\infty {\det ({A_i})} =\ . . .$
A $\frac{{{a^2}}}{{{{(1 - a)}^2}}} - \frac{{{b^2}}}{{{{(1 - b)}^2}}}$ B $\frac{{{a^2} - {b^2}}}{{(1 - {a^2})(1 - {b^2})}}$ C $\frac{{{a^2}}}{{{{(1 - a)}^2}}} + \frac{{{b^2}}}{{{{(1 - b)}^2}}}$ D $\frac{{{a^2}}}{{{{(1 + a)}^2}}} - \frac{{{b^2}}}{{{{(1 + b)}^2}}}$ Download our app for free and get started Solution
B $\frac{{{a^2} - {b^2}}}{{(1 - {a^2})(1 - {b^2})}}$
$|{A_i}| = \left| {\,\begin{array}{*{20}{c}}{{a^i}}&{{b^i}}\\{{b^i}}&{{a^i}}\end{array}\,} \right| = {({a^i})^2} - {({b^i})^2}$,
$|a|\, < 1,|b|\, < 1$
$\sum\limits_{i = 1}^\infty {|{A_i}|} = ({a^2} - {b^2}) + ({a^4} - {b^4}) + ({a^6} - {b^6}) + .......$
$ = ({a^2} + {a^4} + {a^6} + ......)$
$ - ({b^2} + {b^4} + {b^6} + .......)$
$ = \frac{{{a^2}}}{{1 - {a^2}}} - \frac{{{b^2}}}{{1 - {b^2}}}$
$ = \frac{{{a^2} - {a^2}{b^2} - {b^2} + {a^2}{b^2}}}{{(1 - {a^2})(1 - {b^2})}}$
$ = \frac{{{a^2} - {b^2}}}{{(1 - {a^2})(1 - {b^2})}}$.