... xxxxxxxxxcossinsincossincossinsincos22−+−=−⇔0,25 ⇔ )2 sin1(sinsincos xxxx −=− ⇔ 0)1 sincos)(sinsin(cos2=−−− xxxxx 0,25 ⇔0 )3 2 cos 2 )( sinsin(cos=−+−xxxx (cos )( 2 sin(2 ) 3) 04x ... : M (- 1 ;0 ; 4) 0,25VI.a 1 1Bpt ( ) ( ) 432 322222≤−++⇔−−xxxx0,25 ( ) )0 (3 2 22>+=−ttxx BPTTT : 41≤+tt 24 1 0t t⇔ − + ≤ 32 32+≤≤−⇔t (tm)0,25Khi ®ã : ( ) 32 3 232 22+≤+≤−− ... IV 1 1 .Ta có :VT =2 2 2 ( ) ( ) a b c b c aA Bb c c a a b b c c a a b+ + + + + = ++ + + + + + 0,25 [ ] 3 31 1 1 1 3 ( ) ( ) ( ) 21 1 1 1 9 3 ( )( )( )3 2 2 3 2A a b b c c aa b b c...