2 1 ( a + b α + c α 2 + d α 3 ) + 2 1 ( a + b β + c β 2 + d β 3 )
If α and β are roots to the equation 6 x 2 − 6 x + 1 = 0 , and the value of the expression above can be expressed as p a + q b + r c + s d for integers p , q , r and s , find the value of p ⋅ q r ⋅ s .
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That Calligraphy Kills me everytime.
Nice solution man
Woah! Nice problem + solution again!
Newton's sums made it easy !!
We will first start by finding the roots of the equation : 6 x 2 − 6 x + 1 = 0 and we do so by the "Quadratic formula" : x = 2 a − b ± b 2 − 4 a c where a = 6 , b = − 6 , c = 1
we therefore get that the two roots are 6 3 + 3 , 6 3 − 3 and we can say that α = 6 3 + 3 , β = 6 3 − 3 now the problem is simple , all we have to do is rearrange the equation , and equate coefficients : 2 1 ( a + b α + c α 2 + d α 3 ) + 2 1 ( a + b β + c β 2 + d β 3 ) = a + 2 1 b ( α + β ) + 2 1 c ( α 2 + β 2 ) + 2 1 d ( α 3 + β 3 ) and this equation can be written as : p a + q b + r c + s d therefore by equating coefficients one finds : p 1 = 1 , q 1 = 2 α + β , r 1 = 2 α 2 + β 2 , s 1 = 2 α 3 + β 3 and by computing these values one finds : p = 1 , q = 2 , r = 3 , s = 4 Therefore p . q r . s = 1 ∗ 2 3 ∗ 4 = 2 1 2 = 6
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