Given `f(x)=x^4-2x^3+6x-4` we are asked to find the concavity intervals and inflection points:
If the second derivative of a function is positive the function is concave up; if the second derivative is negative the function is concave down.
Inflection points occur when the sign of the second derivative changes.
So we find the second derivative:
`f'(x)=4x^3-6x^2+6`
`f''(x)=12x^2-12x`
Set the second derivative equal to zero:
`12x^2-12x=0==>12x(x-1)=0==>x=0,x=1`
Consider the sign of the second derivative on the following intervals:
`f''(x)>0 (-oo,0)`
`f''(x)<0 (0,1)`
`f''(x)>0 (1,oo)`
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The function is concave up on `(-oo,0),(1,oo)` and concave down on (0,1). The points of inflection are (0,-4) and (1,1)
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The graph:
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