弱问数学几个...

tititalinUID: 2204754

1.The sum of two numbers that differ by 1 is t. In terms of t, what is the value of the greater of the two numbers?
A.(t-1)/2
B.t/2
C.(t+1)/2
D.(t/2)+1
) x6 x% Z5 l7 A/ fE.(2t-1)/2
* q) a/ G% X; ^1 e; z$ W& Y答案为C?!... 题懂了...但是怎么选的哦?!
: o* f. {4 G8 w5 Q- A
2.At time t=0, a ball was thrown upward from an initial height of 6 feet. Until the ball hit the ground, its height, in feet, after t seconds was given by the function h here:
+ g4 O" N8 r* D0 Ih(t)= c-(d-4t)的平方, in which c and d are positive constants. If the ball reached its maximum height of 106 feet at time t=2.5, what was the height, in feet , of the ball at time t=1?

5 H# b; y8 |. o3 U* g题懂...但是....55555偶觉得数据不够呢?...偶函数学的不怎么样.......
+ A; K) z) S! P; F5 I+ m
( g2 J2 E. e8 f6 @# O+ s/ F谢谢!!!!

magic_gatheringUID: 2217174

Assume the greater one is x ,the smaller one is x-1,
so t=x+x-1=2x-1
$ U% @* H: O, Win reverse,x=(t+1)/2
  g' r) e% H! Oso C is the right answer

8 Y. q% u7 ]6 S7 }+ C) p+ LIt is clear~~~

hyacinthUID: 2184492

t=0的时候高度是6
t=2.5高度是106
联立方程组就可以求出c,d

tititalinUID: 2204754

谢谢!!!!!!