Proof of inequality using Cauchy–Schwarz inequality












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How I can prove this inequality? How can I prove it using Cauchy–Schwarz inequality?



Let $a_1,...,a_n,b_1,....,b_n$ are any real numbers.



$sqrt {sum_{k=1}^n (a_k+b_k)^2)} leq sqrt {sum_{k=1}^n {a_k}^2} sqrt {sum_{k=1}^n {b_k}^2}$










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    0












    $begingroup$


    How I can prove this inequality? How can I prove it using Cauchy–Schwarz inequality?



    Let $a_1,...,a_n,b_1,....,b_n$ are any real numbers.



    $sqrt {sum_{k=1}^n (a_k+b_k)^2)} leq sqrt {sum_{k=1}^n {a_k}^2} sqrt {sum_{k=1}^n {b_k}^2}$










    share|cite|improve this question











    $endgroup$















      0












      0








      0





      $begingroup$


      How I can prove this inequality? How can I prove it using Cauchy–Schwarz inequality?



      Let $a_1,...,a_n,b_1,....,b_n$ are any real numbers.



      $sqrt {sum_{k=1}^n (a_k+b_k)^2)} leq sqrt {sum_{k=1}^n {a_k}^2} sqrt {sum_{k=1}^n {b_k}^2}$










      share|cite|improve this question











      $endgroup$




      How I can prove this inequality? How can I prove it using Cauchy–Schwarz inequality?



      Let $a_1,...,a_n,b_1,....,b_n$ are any real numbers.



      $sqrt {sum_{k=1}^n (a_k+b_k)^2)} leq sqrt {sum_{k=1}^n {a_k}^2} sqrt {sum_{k=1}^n {b_k}^2}$







      real-analysis analysis inequality






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      edited Jan 19 at 0:09









      Bernard

      121k740116




      121k740116










      asked Jan 19 at 0:00









      AlarAlar

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          This is false when $a_1 = b_1= 1$ and $a_k = b_k = 0$ for $k ne 1$.






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            1 Answer
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            $begingroup$

            This is false when $a_1 = b_1= 1$ and $a_k = b_k = 0$ for $k ne 1$.






            share|cite|improve this answer









            $endgroup$


















              4












              $begingroup$

              This is false when $a_1 = b_1= 1$ and $a_k = b_k = 0$ for $k ne 1$.






              share|cite|improve this answer









              $endgroup$
















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                4








                4





                $begingroup$

                This is false when $a_1 = b_1= 1$ and $a_k = b_k = 0$ for $k ne 1$.






                share|cite|improve this answer









                $endgroup$



                This is false when $a_1 = b_1= 1$ and $a_k = b_k = 0$ for $k ne 1$.







                share|cite|improve this answer












                share|cite|improve this answer



                share|cite|improve this answer










                answered Jan 19 at 0:05









                angryavianangryavian

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