Sederhanakan [tex]\large \frac{\left ( x^\frac{1}{3}-x^\frac{1}{6} \right )\left ( x^\frac{1}{2}+x \right )\left

Berikut ini adalah pertanyaan dari syakhayaz pada mata pelajaran Matematika untuk jenjang Sekolah Menengah Atas

Sederhanakan\large \frac{\left ( x^\frac{1}{3}-x^\frac{1}{6} \right )\left ( x^\frac{1}{2}+x \right )\left ( x^\frac{1}{2}+x^\frac{1}{3}+x^\frac{2}{3} \right )}{\left ( x^\frac{4}{3}-x \right )\left ( x+x^\frac{1}{3}+x^\frac{2}{3} \right )}

Jawaban dan Penjelasan

Berikut ini adalah pilihan jawaban terbaik dari pertanyaan diatas.

\large\text{$\begin{aligned}\frac{\left(x^{\frac{1}{3}}-x^{\frac{1}{6}}\right)\left(x^{\frac{1}{2}}+x\right)\left(x^{\frac{1}{2}}+x^{\frac{1}{3}}+x^{\frac{2}{3}}\right)}{\left(x^{\frac{4}{3}}-x\right)\left(x+x^{\frac{1}{3}}+x^{\frac{2}{3}}\right)}\end{aligned}$}
dapat disederhanakan menjadi:
\large\text{$\begin{aligned}\boxed{\vphantom{\Bigg|}\ \frac{1}{x^{\frac{1}{3}}}\ {\sf atau}\ \frac{1}{\sqrt[3]{x}}\ {\sf atau}\ x^{-\frac{1}{3}}\ }\end{aligned}$}

Penjelasan dengan langkah-langkah:

Kita akan menyederhanakan

\large\text{$\begin{aligned}\frac{\left(x^{\frac{1}{3}}-x^{\frac{1}{6}}\right)\left(x^{\frac{1}{2}}+x\right)\left(x^{\frac{1}{2}}+x^{\frac{1}{3}}+x^{\frac{2}{3}}\right)}{\left(x^{\frac{4}{3}}-x\right)\left(x+x^{\frac{1}{3}}+x^{\frac{2}{3}}\right)}\end{aligned}$}

Untuk mempermudah, kita gunakan pemisalan.

Pangkat terkecil terdapat pada x^{\frac{1}{6}}.

Ambil a = x^{\frac{1}{6}}, maka pecahan tersebut dapat dinyatakan dan disederhanakan dengan:

\large\text{$\begin{aligned}&\frac{\left(a^2-a\right)\left(a^3+a^6\right)\left(a^3+a^2+a^4\right)}{\left(a^8-a^6\right)\left(a^6+a^2+a^4\right)}\\&{=\ }\frac{a\left(a-1\right)a^3\left(1+a^3\right)a^2\left(a+1+a^2\right)}{a^6\left(a^2-1\right)a^2\left(a^4+1+a^2\right)}\\&{=\ }\frac{\cancel{a^6}\left(a-1\right)\left(1+a^3\right)\left(a+1+a^2\right)}{\cancel{a^6}\cdot a^2\left(a^2-1\right)\left(a^4+1+a^2\right)}\end{aligned}$}
\large\text{$\begin{aligned}&{=\ }\frac{\left(a-1\right)\left(1+a^3\right)\left(a+1+a^2\right)}{a^2\left(a^2-1\right)\left(a^4+1+a^2\right)}\\&{=\ }\frac{\cancel{(a-1)}\left(1+a^3\right)\left(a+1+a^2\right)}{a^2(a+1)\cancel{(a-1)}\left(a^4+1+a^2\right)}\\&{=\ }\frac{\left(1+a^3\right)\left(a+1+a^2\right)}{a^2(a+1)\left(a^4+1+a^2\right)}\\&{=\ }\frac{\cancel{(a+1)}\left(a^2-a+1\right)\left(a+1+a^2\right)}{a^2\cancel{(a+1)}\left(a^4+1+a^2\right)}\\\end{aligned}$}
\large\text{$\begin{aligned}&{=\ }\frac{\left(a^2-a+1\right)\left(a+1+a^2\right)}{a^2\left(a^4+1+a^2\right)}\\&{=\ }\frac{\left(a^2-a\right)\left(a^2+a\right)+\left(a^2-a\right)+\left(a^2+a\right)+1}{a^2\left(a^4+1+a^2\right)}\\&{=\ }\frac{a^4-a^2+2a^2+1}{a^2\left(a^4+1+a^2\right)}\\&{=\ }\frac{\cancel{a^4+a^2+1}}{a^2\cancel{\left(a^4+1+a^2\right)}}\\&{=\ }\frac{1}{a^2}\end{aligned}$}

Substitusi akembali denganx^{\frac{1}{6}}, menghasilkan:

\large\text{$\begin{aligned}&\frac{\left(x^{\frac{1}{3}}-x^{\frac{1}{6}}\right)\left(x^{\frac{1}{2}}+x\right)\left(x^{\frac{1}{2}}+x^{\frac{1}{3}}+x^{\frac{2}{3}}\right)}{\left(x^{\frac{4}{3}}-x\right)\left(x+x^{\frac{1}{3}}+x^{\frac{2}{3}}\right)}\\&{=\ }\frac{1}{\left(x^{\frac{1}{6}}\right)^2}\\&{=\ }\boxed{\vphantom{\Bigg|}\,\frac{1}{x^{\frac{1}{3}}}=\frac{1}{\sqrt[3]{x}}=x^{-\frac{1}{3}}\,}\end{aligned}$}
\blacksquare

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Last Update: Sat, 11 Mar 23