结果一定是一样的,不化简做越来比较费事.
利用商的求导法则求导后化简也行,运算量较大.
y'=[(1-√x)/(2√x)+(1+√x)/(2√x)]/(1-√x)²+[-(1+√x)/(2√x)-(1-√x)/(2√x)]/(1+√x)²
=1/[√x(1-√x)²]-1/[√x(1+√x)²]
=[(1+√x)²-(1-√x)²]/[√x(1-√x)²(1+√x)²]
=(4√x)/[√x(1-x)²]
=4/(1-x)².
另:y=2(1+x)/(1-x),y'=[2(1-x)+2(1+x)]/(1-x)²=4/(1-x)².