formula

\[x^{n}-y^{n}=(x-y)(x^{n-1}+x^{n-2}y+\cdots+xy^{n-2}+y^{n-1})\]

'Beauty is truth, truth beauty,'-that is all Ye know on earth, and all ye need to know.
John Keats,"Ode on a Grecian Urn"





















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