m=f(0)=49
f(x)=(x^2-49)*(x^2-1)≤49
Fie g(x)=f(x)-49
g(x)=(x²-49)(x²-1)-49
g(x)=x⁴-50x²
g(x)=x⁴-50x²=0
x²(x²-50)=0
x1=0 x2=-5√2 x3=5√2
Tabel de variatie
x l-∞................................-5√2......0.....+5√2.................+∞
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x l_ - - - - - - - - -0+ + + + + +
x^2-50l+ + + + + 0------------------0+ + +
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g(x) l- - - - - - --0++++++0- - - 0+ + +
Iei in considerare intervalele pe care g(x) este negativa sau 0
x∈ (-∞ ,0]U{0} care e o multime nemarginita
