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Mathematics

Show that: [xaxb]ab.[xbxc]bc.[xcxa]ca=1\Big[\dfrac{x^a}{x^{-b}}\Big]^{a-b}.\Big[\dfrac{x^b}{x^{-c}}\Big]^{b-c}.\Big[\dfrac{x^c}{x^{-a}}\Big]^{c-a} = 1

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Answer

To prove: [xaxb]ab.[xbxc]bc.[xcxa]ca=1\Big[\dfrac{x^a}{x^{-b}}\Big]^{a-b}.\Big[\dfrac{x^b}{x^{-c}}\Big]^{b-c}.\Big[\dfrac{x^c}{x^{-a}}\Big]^{c-a} = 1

Taking LHS:

[xaxb]ab.[xbxc]bc.[xcxa]ca=[xa(ab)xb(ab)].[xb(bc)xc(bc)].[xc(ca)xa(ca)]=[xa2abxab+b2].[xb2bcxbc+c2].[xc2acxac+a2]=[x(a2ab)(ab+b2)].[x(b2bc)(bc+c2)].[x(c2ac)(ac+a2)]=[xa2ab+abb2].[xb2bc+bcc2].[xc2ac+aca2]=[xa2b2].[xb2c2].[xc2a2]=x(a2b2)+(b2c2)+(c2a2)=xa2b2+b2c2+c2a2=x0=1=RHS\Big[\dfrac{x^a}{x^{-b}}\Big]^{a-b}.\Big[\dfrac{x^b}{x^{-c}}\Big]^{b-c}.\Big[\dfrac{x^c}{x^{-a}}\Big]^{c-a}\\[1em] = \Big[\dfrac{x^{a(a-b)}}{x^{-b(a-b)}}\Big].\Big[\dfrac{x^{b(b-c)}}{x^{-c(b-c)}}\Big].\Big[\dfrac{x^{c(c-a)}}{x^{-a(c-a)}}\Big]\\[1em] = \Big[\dfrac{x^{a^2-ab}}{x^{-ab+b^2}}\Big].\Big[\dfrac{x^{b^2-bc}}{x^{-bc+c^2}}\Big].\Big[\dfrac{x^{c^2-ac}}{x^{-ac+a^2}}\Big]\\[1em] = \Big[{x^{(a^2-ab)-(-ab+b^2)}}\Big].\Big[x^{(b^2-bc)-(-bc+c^2)}\Big].\Big[x^{(c^2-ac)-(-ac+a^2)}\Big]\\[1em] = \Big[{x^{a^2-ab+ab-b^2}}\Big].\Big[x^{b^2-bc+bc-c^2}\Big].\Big[x^{c^2-ac+ac-a^2}\Big]\\[1em] = \Big[x^{a^2-b^2}\Big].\Big[x^{b^2-c^2}\Big].\Big[x^{c^2-a^2}\Big]\\[1em] = x^{(a^2-b^2)+(b^2-c^2)+(c^2-a^2)}\\[1em] = x^{a^2-b^2+b^2-c^2+c^2-a^2}\\[1em] = x^0\\[1em] = 1 \\[1em] = \text{RHS}

∴ LHS = RHS

[xaxb]ab.[xbxc]bc.[xcxa]ca=1\Big[\dfrac{x^a}{x^{-b}}\Big]^{a-b}.\Big[\dfrac{x^b}{x^{-c}}\Big]^{b-c}.\Big[\dfrac{x^c}{x^{-a}}\Big]^{c-a} = 1

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