:
R0 = 0, M0 = 0. (4.2)
, :
1) :
S MA = 0;
S X = 0; (4.3)
S Y = 0.
2) :
S MA = 0;
S MB = 0; (4.4)
S Y = 0, Oy .
3) :
S MA = 0;
S MB = 0; (4.5)
S M = 0, , .
, (4.3), (4.4) (4.5) (4.2) .
, R0 = 0 , ½ R0 ½= R0 = 0. (4.1): R0 2 = (S X)2 + (S Y)2 = 0, (4.2).
(4.3) , .
, (4.4) (4.2).
(4.4) :
1) , , ;
2) , , , .
(4.4). - :
1) R = 0;
2) R ¹ 0 .
(4.4), , Ry = S Yi = 0.
, R , R = 0, .
, (4.2) (4.3) (4.5).
:
1. (4.3), (4.4) (4.5) . , .
, Oy (4.3) , , , .
, .
2. , Oy, :
1) :
S MA = 0; (4.6)
S Y = 0, Oy .
2) :
S MA = 0; (4.7)
S MB = 0, .
3. , , , , (4.3)-(4.5) (4.6) (4.7) (2.10) .
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5.
, , , .
. , .
, , , , . /2 ( = /2).
, . q /.
, [ a, b ] , q = q (x). . :
:
Q = .
, , , , , . , , .
. 1.5.
, , (.1.8) , , XA = RA YA = RAY, .
(.5.1) , . , .
, . , , MA, XA YA.
, (.5.2). : RA = YA, XA = 0.
5.1. (.5.3).
. Q = (1/2)× aq = (1/2)×3×2 = 3, 1 , = = 2 , .
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, , RA (.5.3).
(4.7), (4.6) RA R .
S MA = 0; - Q ×1 + R ×3 - M + ×5 = 0,
R = (1/3) (Q + M - ×5) = (1/3) (3 + 4 - 2×5) = - 1.
S MB = 0; - RA ×3 + Q ×2 - M + ×2 = 0, ð
RA = (1/3) (Q ×2 - M + ×2) = (1/3) (3×2 - 4 + 2×2) = 2 .
, (4.6):
S Yi = RA - Q + R + = 2 - 3 - 1 + 2 = 0,
, .
5.2. , (.5.4).
. . , . : Q 1 = (1/2)×3×2 = 3 Q 2 = (1/2)×3×4 = = 6 , (.5.4).
RA MA, , (4.6):
S MA = 0; ð MA = 15 ×;
S Y = 0, ð RA = 9 .
S M = 0, :
S M = MA - RA ×3 + Q 1×2 + Q 2×1 = 15 - 27 + 6 +6 = 0.
. .