2 ( 2 x − 1 ) x 2 + ( 2 x 2 − 2 ) x = 2 x + 1 − 2 Find the number of real solutions x which satisfy the above equation.
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At the beginning, your factorization is not : x^(x^2-1) insted of 2^(x^2-1) ?
graphs work by making the equation look like 2^(x^2) = 2(x^2+x-2)/x
I took a more naive approach. Rhs = 2(2^x - 1). By making Rhs 0, the 1st part of Lhs can become 2(2^x - 1)(x^2 - 1). The 2nd part of LHS can be represented as 2(2^[x^2-1] - 1)x. The sum of the 2 parts should end up as zero. This happens when x =0 or when x^2 -1 =0. So there are 3 answers. (I first misread the question and tried to answer with actual solutions...)
I think trial and error would be an appropriate . So there are three soutions at x= -1, 0, and 1.
TRY and ERROR Solutions. The number is starting with 0,1, -1, 2,-2 etc..but the largest number are not possible, and then we got the answer. The correct answer as the solutions of that equation are 0,-1, and 1. When we enter "0" to the equation, we got 0 = 0 when we enter "-1" , we got -1 = -1 when we enter "1", we got 2 = 2
Is there a more methodical approach one could take to this problem? I did it by trial and error, but that's not satisfying to me.
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F(x) =2(2^x-1)*x^2+(2^x^2-2)x-2^(x+1)+2 then f(0)=0, f(1)=0,f(-1)=0 As x tends to infinity f(x) tends to infinity and as x tends to negative infinity f(x) tends to negative infinity hence only 3 roots
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we have 2 ( 2 x − 1 ) x 2 + ( 2 x 2 − 2 ) x = 2 x + 1 − 2 we can transform it as 2 ∗ 2 x ∗ x 2 − 2 ∗ x 2 + 2 ∗ x x 2 − 2 ∗ x = 2 ∗ 2 x − 2 now we factorize as following : 2 ∗ 2 x ( x 2 − 1 ) − 2 ∗ ( x 2 − 1 ) + 2 ∗ x ( 2 x 2 − 1 − 1 ) let y = x 2 − 1 and then we have 2 ∗ 2 x ∗ y − 2 ∗ y + 2 ∗ x ( 2 y − 1 ) if y=0 the equation has two roots x1=1 and x2=2.the equation has one more root x3=0. we have to prove that the equation has no more roots. let assume that the equation has roots for y=/0 and x=/0.
we multiply the equation by 1 / ( y ∗ x ) . then we have ( 2 / x ) ∗ 2 x − ( 2 / x ) + ( 2 / y ) ( 2 y − 1 ) = 0 or ( 2 / x ) ∗ ( 2 x − 1 ) = − ( 2 / y ) ∗ ( 2 y − 1 ) or ( 2 / x ) / ( 2 / y ) = − ( 2 y − 1 ) / ( 2 x − 1 ) or y / x = − ( 2 y − 1 ) / ( 2 x − 1 ) or ( 2 x − 1 ) / x = − ( 2 y − 1 ) / y where y=x^2 -1
let f(x)=(2^x-1)/x.if we prove that there is no x for the expression f ( x ) = − f ( x 2 − 1 ) to be true then the initial equation has no more than the three above roots.
but f(x)>0 for every x, because : -if x>0 then 2^x-1>0 and ( 2 x − 1 ) / x > 0 -if x<0 2^x-1<0 and ( 2 x − 1 ) / x > 0
so f(x)>0 for every real x and so we have that f(x^2-1)>0. but f(x)>0 and -(f(x^2-1))<0 and there is no x in order to f(x)=-(f(x^2-1)).
thereof the initial equation has exactly three roots x1=1, x2=-1 and x3=0.