Gui TremBle ve bai toan vua roi?

The nay nhe : ban lay giay nhap ra ve duong cong bac 3 co 2 cuc tri tren he truc toa do Oxy ( nho la he so a > 0 ) sao cho no cat truc Ox tai 3 diem pb co hoanh do > 0

Ban se thay :

1) Diem cuc dai o phia tren truc hoanh do do : f(xcd) > 0

2) Diem cuc tieu o phia duoi truc hoanh do do : f(xct) < 0

3) Hoanh do diem cuc dai xcd va cuc tieu xct o ben phai truc tung nen 0 < xcd < xct ( do do chi can dieu kien xct > 0)

4) Do thi cat truc tung tai diem co tung do < 0 nen f(0) < 0

Doi voi bai toan tren neu de bai yeu cau x < 0 thi o dieu kien 3) ta phai xet xct < 0 va dieu kien 4) la f(0) > 0