Math, asked by SunilDhiman1020, 1 year ago

if x+1/x =13 find xcube +1/xcube​

Answers

Answered by RajRockers
3

Step-by-step explanation:

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Answered by Anonymous
9

Step-by-step explanation:

Given,

 \mathsf{x +  \frac{1}{x}  = 13}

To find:

 \mathsf{x {}^{3} +  \frac{1}{x {}^{3} }  }

Of the form,

(a+b)³=a³+b³+3ab(a+b)

Here,

 \sf{a = x \:  \: and \:  \: b =  \frac{1}{x} }

Putting the values

 \mathsf{(x +  \frac{1}{x}) {}^{3} = x {}^{3}  +  \frac{1}{x {}^{3} }  + 3(x +  \frac{1}{x})  } \\  \\  \implies \:  \sf{13 {}^{3}  =x {}^{3} +  \frac{1}{x {}^{3}}  + 3(13) \: } \\  \\  \implies \:  \sf{x {}^{3} +  \frac{1}{x {}^{3} } = 2197 - 39  } \\  \\  \implies \:  \sf{x {}^{3} +  \frac{1}{x {}^{3} \: }  = 2158 }

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