Question

fx=3x²-4x+1的单调区间

Answer 1

f(x)=3(x^2-4x/3+1/3)
=3[(x-2/3)^2+1/3-4/9]
=3(x-2/3)^2-1/3
所以当x<2/3时，f(x)单调递减；当x>2/3时，f(x)单调递增

Answer 2

f(x)
=3x^2-4x+1
=3[x^2 - (4/3)x] +1
=3[x^2 - (4/3)x + 4/9] +1 - 4/3
=3(x-2/3)^2 - 1/3
单调
增加 = [2/3, +∞)
减小=(-∞, 2/3]