If you randomly picked one root of the function p ( x ) = ( x 4 + 1 9 8 9 x 3 − 8 1 6 2 7 4 2 x 2 + 2 0 2 8 0 9 8 0 0 x ) ( e 2 0 1 4 x − 1 ) [ ln ( x − 1 0 0 6 9 ) ] and the function is from R to R , what is the probability that the root that you picked is divisible by 2 0 1 4 ?
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You have to specify that the function is from R to R . Also, it turns out that x ( x − 2 5 ) ( x − 2 0 1 4 ) ( x + 4 0 2 8 ) = x 4 + 2 0 0 9 x 3 − 8 1 2 2 4 6 2 x 2 + 4 0 5 6 1 9 6 0 x .
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But − 2 5 × − 2 0 1 4 × 4 0 2 8 = 2 0 2 8 0 9 8 0 0 and not 4 0 5 6 1 9 6 0
− 2 5 − 2 0 1 4 + 4 0 2 8 = 1 9 8 9 not 2 0 0 9
and ( − 2 5 × − 2 0 1 4 ) + ( − 2 0 1 4 × 4 0 2 8 ) + ( 4 0 2 8 × − 2 5 ) = − 8 1 6 2 7 4 7 not − 8 1 2 2 4 6 2
So its correct.
No Sorry but you made a mistake. The roots of the polynomial that you made are 5, 2014, and -4028
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Yeah, that's my point. Your polynomial's roots are slightly off from 5, 2014 and -4028.
But ok I will add R to R
Mother of mercy, that was sneaky!
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Let f ( x ) = x 4 + 1 9 8 9 x 3 − 8 1 6 2 7 4 7 x 2 + 2 0 2 8 0 9 8 0 0 x
also g ( x ) = e 2 0 1 4 x − 1
and h ( x ) = ln ( x − 1 0 0 6 9 )
We must equate all these factors to 0 .
Factoring f ( x ) we will get
f ( x ) = x ( x − 2 5 ) ( x − 2 0 1 4 ) ( x + 4 0 2 8 ) = 0
Thus the roots of f ( x ) are x = 0 , 2 5 , 2 0 1 4 , − 4 0 2 8
Equating g ( x ) = 0 gives
g ( x ) = 0
e 2 0 1 4 x − 1 = 0
e 2 0 1 4 x = 1
e 2 0 1 4 x = e 0
2 0 1 4 x = 0
x = 0
Equating h ( x ) = 0 gives
h ( x ) = 0
ln ( x − 1 0 0 6 9 ) = 0
ln ( x − 1 0 0 6 9 ) = ln 1
x − 1 0 0 6 9 = 1
x = 1 0 0 7 0 .
These are not yet the roots of p ( x ) . To get the roots of p ( x ) , we must SUBSTITUTE them back to the original equation.
Only x = 1 0 0 7 0 satisfies p ( x ) = 0 since the other values of x makes the natural logarithm part undefined.
Since 1 0 0 7 0 is divisible by 2 0 1 4 , the probability will be 1 0 0 %