SAT数学题请翻译再作答谢谢.foranycube,ifthevolumeisVcubicinchesandthesurfaceareaisAsquareinches,thenVisdirectlyproportionaltowhichofthefollowing?A.AB.A^2C.A^3D.A^(2/3)E.A^(3/2)thepositivenumbernistheproduc

Question

SAT数学题
请翻译再作答谢谢.
for any cube,if the volume is V cubic inches and the surface area is A square inches,then V is directly proportional to which of the following?
A.A B.A^2 C.A^3 D.A^(2/3) E.A^(3/2)
the positive number n is the product of three different prime numbers greater than 2,if the sum of these prime number is also prime ,what is the smallest possible value for

Answer 1

1 对于任何一个正方体来说,如果它的体积是V立方英寸,表面积是A平方英寸,那么V与一下那个选项成比例?
设该正方体的边长为L,对于正方体来说：V=L3 A=6*L2 把L用A表示为：L=(A/6)^(1/2)将此结果带入V=L3中,可得V=(A/6)^(3/2),因为(1/6)^(3/2)为常数,所以V与A^(3/2)成比例
2 正数n是3个比2大的不同的质数的乘积.如果这三个质数的仍然是个质数,那么n最小是什么?
为了使n最小,那三个质数也应该尽可能的小.这题我就是凑出来的.3+5+7=15,非质数,排除.3+5+9=17,质数,所以n最小为135