KnowledgeBoat Logo
|

Mathematics

Simplify the following:

(x13x13)(x23+1+x23)\Big(x^{\dfrac{1}{3}} - x^{-\dfrac{1}{3}}\Big)\Big(x^{\dfrac{2}{3}} + 1 + x^{-\dfrac{2}{3}}\Big)

Indices

38 Likes

Answer

The above equation can be written as,

(x13x13)[(x13)2+x13.x13+(x13)2)\Rightarrow \Big(x^{\dfrac{1}{3}} - x^{-\dfrac{1}{3}}\Big)\Big[\Big(x^{\dfrac{1}{3}}\Big)^2 + x^{\dfrac{1}{3}}.x^{-\dfrac{1}{3}} + \Big(x^{-\dfrac{1}{3}}\Big)^2\Big)

We know that,

a3 - b3 = (a - b)(a2 + ab + b2)

(x13x13)[(x13)2+x13.x13+(x13)2]=(x13)3(x13)3(x3×13)(x3×13)x1x1x1x.\therefore \Big(x^{\dfrac{1}{3}} - x^{-\dfrac{1}{3}}\Big)\Big[\Big(x^{\dfrac{1}{3}}\Big)^2 + x^{\dfrac{1}{3}}.x^{-\dfrac{1}{3}} + \Big(x^{-\dfrac{1}{3}}\Big)^2\Big] = \Big(x^{\dfrac{1}{3}}\Big)^3 - \Big(x^{-\dfrac{1}{3}}\Big)^3 \\[1em] \Rightarrow \Big(x^{3 \times \dfrac{1}{3}}\Big) - \Big(x^{3 \times -\dfrac{1}{3}}\Big) \\[1em] \Rightarrow x^1 - x^{-1} \\[1em] \Rightarrow x - \dfrac{1}{x}.

Hence, (x13x13)(x23+1+x23)=x1x\Big(x^{\dfrac{1}{3}} - x^{-\dfrac{1}{3}}\Big)\Big(x^{\dfrac{2}{3}} + 1 + x^{-\dfrac{2}{3}}\Big) = x - \dfrac{1}{x}.

Answered By

20 Likes


Related Questions