(a^2+b^2+c^2)-(a^2-b^2-c^2) (A+b+c+d)^2+(a+b-c-d)+(a+c-b-d)^2+(a+d-b-c)^2

0 bình luận về “(a^2+b^2+c^2)-(a^2-b^2-c^2) (A+b+c+d)^2+(a+b-c-d)+(a+c-b-d)^2+(a+d-b-c)^2”

1. Đáp án:

    $a) 2b^2+2c^2\\
   b)
   4a^2+4b^2+4c^2\\$

   Giải thích các bước giải:

    $a) (a^2+b^2+c^2)-(a^2-b^2-c^2)=a^2+b^2+c^2-a^2+b^2+c^2=2b^2+2c^2\\
   b)
   (a+b+c+d)^2+(a+b-c-d)^2+(a+c-b-d)^2+(a+d-b-c)^2\\
   =a^2+b^2+c^2+d^2+2ab+2ac+2ad+2bc+2bd+2cd+a^2+b^2+c^2+d^2-2ac+2ab-2ad-2bc+2cd-2bd+a^2+c^2+b^2+d^2+2ac-2ab-2ad-2bc-2cd+2bd+a^2+d^2+b^2+c^2+2ad-2ab-2ac-2bd-2cd+2bc\\
   =4a^2+4b^2+4c^2\\$

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