\(A=\dfrac{5}{2}-\dfrac{1}{4x^2}+\sqrt{4^2.5+1}\)
\(A=\dfrac{5}{2}-\dfrac{1}{4x^2}+\sqrt{16.5+1}\)
\(A=\dfrac{5}{2}-\dfrac{1}{4x^2}+\sqrt{81}\)
\(A=\dfrac{5}{2}-\dfrac{1}{4x^2}+\sqrt{9^2}\)
\(A=\dfrac{5}{2}-\dfrac{1}{4x^2}+9\)
\(A=\dfrac{10x^2}{4x^2}-\dfrac{1}{4x^2}+\dfrac{36x^2}{4x^2}\)
\(A=\dfrac{10x^2-1+36x^2}{4x^2}\)
\(A=\dfrac{\left(10x^2+36x^2\right)-1}{4x^2}\)
\(A=\dfrac{46x^2-1}{4x^2}\)
bạn chx viết rõ đề nên mình làm 2 kiểu:
kiểu 1
`5/2 - 1(4x^2) + `\(\sqrt{4^2.5+1}\)
\(=\dfrac{5}{2}-\dfrac{1}{4x^2}+\sqrt{16.5+1}\)
\(=\dfrac{5}{2}-\dfrac{1}{4x^2}+\sqrt{81}\)
\(\dfrac{5}{2}-\dfrac{1}{4x^2}+9\)
\(\dfrac{23}{2}-\dfrac{1}{4x^2}\)
\(\dfrac{46x^2}{4x^2}-\dfrac{1}{4x^2}=\dfrac{46x^2-1}{4x^2}\)
kiểu 2
\(\dfrac{5}{2}-\dfrac{1}{4.2}+\sqrt{4^2.5+1}\)
\(\dfrac{5}{2}-\dfrac{1}{8}+9\)
\(\dfrac{180}{72}-\dfrac{9}{72}+\dfrac{648}{72}\)
\(\dfrac{180-9+648}{72}=\dfrac{91}{8}\)
` = 2,5 - 0,5 + ( 16 . 5 + 1) `
` = 2,5 - 0,5 + 81 `
` = 83 `
