,菱形周长为2p,两条对角线的和为m,求菱形面积.
问题描述：
,菱形周长为2p,两条对角线的和为m,求菱形面积.
答
设菱形的两条对角线长度分别为x、y,则可知菱形面积S = (xy)/2由勾股定理可知：(x/2)^2 + (y/2)^2 = (2p/4)^2化简得：x^2 + y^2 = p^2又因为：x + y = m所以：S = (xy)/2 = (1/2)*{[(x+y)^2 - (x^2 + y^2)]/2}=(1/4)(...