首先偶函数,(-无穷,0)和(0,+无穷)有相反单调性,只需看(0,正无穷)
1)a0,根据耐克函数,易知(0,4次根a)单调减,(4次根a,+无穷)单调增;(-无穷,负4次根a)单调减,(负4次根a,0)单调增
(-无穷,0)单调性根据偶函数性质,具有相反单调性得到
首先偶函数,(-无穷,0)和(0,+无穷)有相反单调性,只需看(0,正无穷)
1)a0,根据耐克函数,易知(0,4次根a)单调减,(4次根a,+无穷)单调增;(-无穷,负4次根a)单调减,(负4次根a,0)单调增
(-无穷,0)单调性根据偶函数性质,具有相反单调性得到