theo mjnh la bai nạy lam la`(ko bjt dung hem co j sai mong moi nguoi` chi giao):
- vi` h/s dat cuc dai tai A(1;5) => A thuoc do` thj h/s => 5=(a+2+b)/2 <=> a+b=8 (1)
-tinh' dao ham y'=(2ax-2bx-2x^2+2)/(2x+1)^2
vi h/s dat cuc dai tai x=1 => y'(1) =0 <=> (2a-2b)/9 =0 <=> a+b=0 (2)
tu` (1) va` (2) => hpt a + b = 8 => a=4
2a - 2b = 0 b=4
co j sai sot cac ban chi dum mjnh nha