Question

if a+1/a = 4 , then what is a-1/a

Answer 1

Answer:

(a^2 + 1/(a^2) + 2) = 16. (a^2 + 1/(a^2)) = 14.

(a^4 + 1/(a^4) + 2) = 196. (a^4 + 1/(a^4)) = 194.

In the general case, where (a + 1/a) = n , and n an integer, (a^2 + 1/(a^2)) = (n^2 - 2).

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

Answer 2

Answer:

-8/3

Step-by-step explanation:

a+1/a=4

a+1=4a

1=4a-a

3a=1

a=1/3

so a-1/a=(1/3)-1/(1/3)

=(1/3)-3

=(1-9 )/3

= -8/3