Question

2. The sum of (y +9) observations is y4 – 6561. Find the mean of the observations.
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Answer 1

y - 1 / y = t

Squaring on both sides;

(y-1/y)^2=(9)^2 y^2-2XyX1/y+(1/y)^2=81

y^2-2+1/y^2=81

y^2+1/y^2=81+2

y^2+1/y^2=83

Squaring on both the sides, we get;

(y^2+1/y^2)^2=(83)^2

(y^2)^2+2xy^2X1/y^2+(1/y^2)^2=6889

y^4+2+1/y^4=6889

y^4+1/y^4=6889-2

y^4+1/y^4=6887

Answer 2

Answer:

please refer to the above attachment for your answer