S =интеграл (1→4) (√xdx) = x^(1/2+1)/(1/2+1) | 1→4 = (2/3)*√x³ |1→4=
(2/3)(√4³ -√1) =(2/3)(√64 -1) =(2/3)(8 -1) =(2/3)*7 = 14/3 .
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S =интеграл (-3→0) (-(3x +x²)dx) = интеграл (0→(-3)) (3x +x²)dx)=
( 3x²/2 +x³/3) | 0→(-3) =
(3*(-3)²/2 +(-3)³/3) - (3*0²/2 +0³/3) =27/2 - 9 = 4,5.
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-3x - x² =0 ; -(x +3)x =0 ⇒[ x= -3; x=0.
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