... y2 + = 12 y 10 y + = x + 2 (1) 0 ,25 0 ,25 (2) 0 ,25 Ta cú: (1) x + x + = (2 y ) + + (2 y ) (*) Xột hm s c trng f (t ) = t + + t f '(t ) = t t + t2 + t+ t 0 ,25 +1 = > t2 + t2 + t2 + Suy f(t) ... Kho thi THPT quc gia, kim tra cú ỏp ỏn, ti liu ụn thi i hc mụn toỏn Ht H ng d n ch m C õu C õu1.a im 0 ,25 TX : D = R y' = x 8x x = ; y = y' = x = ; y = 0 ,25 Kt lun ng bin nghch bin 0 ,25 ... 1) +) (C) tip xỳc vi (C1 ) II1 = R R1 (1) 0 ,25 0 ,25 +) (C) tip xỳc ngoi vi (C2 ) II = R + R2 R = II R2 (2) +) TH1: R > R1 , (1) R = II1 + R1 , t (1) v (2) ta cú: II1 + R1 = II R2 (a...