... )1(6=xyBµi 2:T×m m ®Ó hµm sè 1)2(6)1(32)(23−−+−+=xmxmxxf cã ®êng th¼ng®i qua C§,CT song song víi ®êng th¼ng baxy+= Gi¶i:.§¹o hµm )2)1((6)('2−+−+=mxmxxf 02)1()(0)('2=−+−+=⇔=mxmxxgxfhµm ... +−−−−==+−−−−==)33(2)3()2(2)33(1)3()1(12222mmxmxfymmxmxfysuy ra ®êng th¼ng qua C§,CT lµ(∆):)33()3(22+−−−−=mmxmy ta cã (∆) song song víi ®êng −±=<⇔−±=−<⇔−=−<≠⇔=−−≠⇔+=amaamaamamammbaxy3030)3(0,3)3(322vËy...