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Polynomials

Question
CBSEENMA9001577

If straight x equals 3 plus 2 square root of 2 comma check whether straight x plus 1 over straight x is rational or irrational.

Solution
x equals 3 plus 2 square root of 2 space space space space space space space space space space space space space space space space space.... left parenthesis 1 right parenthesis
1 over straight x equals fraction numerator 1 over denominator 3 plus 2 square root of 2 end fraction
equals fraction numerator 1 over denominator 3 plus 2 square root of 2 end fraction cross times fraction numerator 3 minus 2 square root of 2 over denominator 3 minus 2 square root of 2 end fraction
equals fraction numerator 3 minus 2 square root of 2 over denominator left parenthesis 3 right parenthesis squared minus left parenthesis 2 square root of 2 right parenthesis squared end fraction
equals space fraction numerator 3 minus 2 square root of 2 over denominator 9 minus 8 end fraction
equals fraction numerator 3 minus 2 square root of 2 over denominator 1 end fraction
equals space 3 minus 2 square root of 2 space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space.... left parenthesis 2 right parenthesis

Adding (1) and (2), we get
straight x plus 1 over straight x equals left parenthesis 3 plus 2 square root of 2 right parenthesis plus left parenthesis 3 minus 2 square root of 2 right parenthesis equals 6

Some More Questions From Polynomials Chapter

Find two rational numbers between 0.1 and 0.2.