if X square + 1 / x square is equal to 27 find the value of x cube minus 1 / x cube
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X² + 1/x² =27
or, x² +1/x² - 2 = 27 - 2
or, x² +1/x² - 2x. 1/x= 27-2
or, (x - 1/x)² =25.
or, (x-1/x) =5
or (x - 1/x)³ =5³ ___(cubing both sides) __
or, x³ - 1/x³ - 3x.1/x (x-1/x) = 125
or, x³ - 1/x³ - 3×5 =125 __(x-1/x =5)___
or, x³ - 1/x³ = 125 + 15 = 140 ___(answer)___
Hope this is ur required answer.
or, x² +1/x² - 2 = 27 - 2
or, x² +1/x² - 2x. 1/x= 27-2
or, (x - 1/x)² =25.
or, (x-1/x) =5
or (x - 1/x)³ =5³ ___(cubing both sides) __
or, x³ - 1/x³ - 3x.1/x (x-1/x) = 125
or, x³ - 1/x³ - 3×5 =125 __(x-1/x =5)___
or, x³ - 1/x³ = 125 + 15 = 140 ___(answer)___
Hope this is ur required answer.
afrazali1:
in second step what do d you do
subtracted 2 in both sides..
but why
to get the whole square
Ok thanks for this
in second step after 2x what do write what is the meaning of point
a² - 2ab + b² thus for 2ab in x and 1/x* we write 2 x × 1/x = 2
Ok understood
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5
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if X square + 1 / x square is equal to 27 find the value of x cube minus 1 / x cube
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