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Vector Algebra

Question
CBSEENMA12032801

Find the area of the smaller part of the circle x2 + y2 = a cut oil by the line straight x equals fraction numerator straight a over denominator square root of 2 end fraction

Solution

The equation of circle is
                   straight x squared minus straight y squared space equals straight a squared                 ...(1)
  The equation of line is
                      straight x space equals space fraction numerator straight a over denominator square root of 2 end fraction                   ...(2)
From (1) and (2), we get,
                     straight a squared over 2 minus straight y squared space equals space straight a squared space space space space or space space space straight y squared space equals space straight a squared over 2
therefore space space space space space straight y space equals space fraction numerator straight a over denominator square root of 2 end fraction
because space space space straight C is open parentheses fraction numerator straight a over denominator square root of 2 end fraction comma space fraction numerator straight a over denominator square root of 2 end fraction close parentheses

 equals space 2 integral subscript fraction numerator straight a over denominator square root of 2 end fraction end subscript superscript straight a straight y space dx space equals space 2 integral subscript fraction numerator straight a over denominator square root of 2 end fraction end subscript superscript straight a square root of straight a squared minus straight x squared end root dx
equals space 2 open square brackets fraction numerator straight x square root of straight a squared minus straight x squared end root over denominator 2 end fraction plus straight a squared over 2 sin to the power of negative 1 end exponent straight x over straight a close square brackets subscript fraction numerator straight a over denominator square root of 2 end fraction end subscript superscript straight a
equals space 2 open parentheses fraction numerator straight a square root of straight a squared minus straight a squared end root over denominator 2 end fraction plus straight a squared over 2 sin to the power of negative 1 end exponent 1 close parentheses space minus space 2 open parentheses fraction numerator straight a over denominator 2 square root of 2 end fraction square root of straight a squared minus straight a squared over 2 end root plus straight a squared over 2 sin to the power of negative 1 end exponent fraction numerator 1 over denominator square root of 2 end fraction close parentheses
equals space 2 open parentheses 0 plus straight a squared over 2 cross times straight pi over 2 close parentheses minus 2 open parentheses fraction numerator straight a over denominator 2 square root of 2 end fraction cross times fraction numerator straight a over denominator square root of 2 end fraction plus straight a squared over 2 cross times straight pi over 4 close parentheses
equals space πa squared over 2 minus straight a squared over 2 minus πa squared over 4 space equals space πa squared over 4 minus straight a squared over 2
equals space straight a squared over 4 left parenthesis straight pi minus 2 right parenthesis space sq. space units
                     

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