Question

Cho C = \(\dfrac{\left(x+5\right)^2+\left(x-5\right)^2}{x^2+25}\) và D = \(\dfrac{\left(2x+5\right)^2+\left(5x-2\right)^2}{x^2+1}\)

Tìm mối quan hệ giữa C và D 

* giúp mk với ạaaaa

 

Answer 1

\(C=\dfrac{\left(x+5\right)^2+\left(x-5\right)^2}{x^2+25}\)

\(=\dfrac{x^2+10x+25+x^2-10x+25}{x^2+25}\)

\(=\dfrac{2x^2+50}{x^2+25}=2\)

\(D=\dfrac{\left(2x+5\right)^2+\left(5x-2\right)^2}{x^2+1}\)

\(=\dfrac{4x^2+20x+25+25x^2-20x+4}{x^2+1}\)

\(=\dfrac{29x^2+29}{x^2+1}=\dfrac{29\left(x^2+1\right)}{x^2+1}=29\)

C=2; D=29

=>\(C=\dfrac{2}{29}D\)