1.

If a2 + 1/a2 = 11, find the value of a3 - 1/a3​

Answer»

ANSWER:

given a^2+1/a^2=11

(a+1/a)^2=13

(a+1/a)=SQRT13

(a-1/a)^2=(a+1/a)^2-4

=13-4=9

(a-1/a)=+or-3

we KNOW that a^3-b^3=(a-b)(a^2+ab+b^2)

a^3-1/a^3=(a-1/a)(a^2+1+1/a^2)

=3(12)

=36



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