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Emanuel Valente <[EMAIL PROTECTED]> said:
> vacilo cara... nao tinha visto!
>
> 4*sen^2(x) -2*(1+raiz2)*sen(x) + raiz2 < 0
> [...]

Complete os quadrados: seja t = sen x.

4t^2 - 2*(1+sqrt(2))*t + sqrt(2) < 0
(2t - (1+sqrt(2))/2)^2 + (2*sqrt(2)-3)/4 < 0
[2t - (1+sqrt(2))/2]^2 < [(sqrt(2) - 1)/2]^2
|2t - (1+sqrt(2))/2| < (sqrt(2) - 1)/2
|4t - 1 - sqrt(2)| < sqrt(2) - 1
1 - sqrt(2) < 4t - 1 - sqrt(2) *e* 4t - 1 - sqrt(2) < sqrt(2) - 1
t > 1/2 *e* t < sqrt(2)/2
1/2 < t < 1/sqrt(2)
1/2 < sen x < 1/sqrt(2).
pi/6 < x < pi/4 *ou* 3*pi/4 < x < 5*pi/6.

[]s,

- -- 
Fábio "ctg \pi" Dias Moreira
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