510: what is the 1st term in sequence S?
1.the 3rd term is 2
2. the 2nd term is twice the 1st, and the 3rd term is 3 times the 2nd
为什么不是C?
534.If the number of square units in the area of a circle is A and the number of linear units in the circumference is C, what is the radius of the circle?
1. A/c=1.5
2. A>C+3
其中的square units 和linear units何解?
多谢! |