Current location - Training Enrollment Network - Mathematics courses - The teacher said that senior high school reviewed the whole process and conceived senior three mathematics.
The teacher said that senior high school reviewed the whole process and conceived senior three mathematics.
The language feature of the teacher's speech is from S5=-20, which is 5a 1+ 10d=-20, that is, a 1+2d=-4. From the conditions, we can know that a6 & gt=0, otherwise S6; =0, that is, d & gt=4/3.