solve the following problem?
if α and β are zeroes of the polynomial 6x^2 + x + 1 , then find the value of :-
(i) α^3 β + α β^3
(ii) α^2 + β^2
(iii) α^2/β + β^2/α
2 Answers
Relevance
- Elizabeth MLv 77 years ago
(α+ß)=-b/a=-1/6, and αß=c/a=1/6
(i) α^3 β + α β^3
=αß(α²+ß²)
=αß[(α+ß)²-2αß]
=(1/6)[1/36 - 1/3]
=-11/216
(ii)α²+ß²
=(α+ß)²-2αß
=1/36-1/3
=-11/36
(iii) α²/ß+ß²/α
=(α³+ß³)/(αß)
=(α+ß)((α+ß)²-3αß)/(αß)
=17/36
- moeLv 77 years ago
6x^2 + x + 1 = 0
Factorize to get:
(6x+1)(x+1) = 0
so,
if(6x+1) = 0 then x = -1/6 or
else (x+1) = 0 then x = -1
so, roots are: -1 (=α) and -1/6(=β)
in which case:
(i) α^3 β + α β^3 =(-1)^3(-1/6) + (-1)(-1/6)^3 = 0.1723
(ii) α^2 + β^2 = (-1)^2 + (1/6)^2 = 1.0278
(iii) α^2/β + β^2/α = (-1)^2/(-1/6) + (-1/6)^2/(-1) = -6.0278
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