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यदि `x=a^(1/2)+a^(-1/2),t=a^(1/2)-a^(-1/2)` है तो `(x^(4)-x^(2)y^(2)-1)+(y^(4)-x^(2)y^(2)+1)` का मान हैA. 13B. 12C. 14D. 16 |
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Answer» Correct Answer - D According to the question `x=sqrt(a)+1/(sqrt(a))` & `y=sqrt(a)-1/(sqrt(a))` `:. x^(4)-x^(2)y^(2)-1+y^(4)-x^(2)y^(2)+1` `=x^(4)-2x^(2)y^(2)+y^(4)` `=[x^(2)-y^(2)]^(2)` `[(sqrt(a)+1/(sqrt(a)))^(2)-(sqrt(a)-1/(sqrt(a)))^(2)]^(2)` `=[a+1/a+2-a-1/a+2]^(2)` `=[4]^(2)=16` |
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