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to cut it short, was asked to find the values of x for which f(x) is an increasing function
[tex] \dfrac{(x^2 + 3)}{4x + 1} = f(x) [/tex]
[tex] \dfrac{(4x-6)(x+2)}{(4x+1)^2} = f'(x) [/tex] so setting this to be greater than zero I get the values of x < -2, and x > 2/3 however in the answers they got x <= -2 and x >= 2/3, and they set f'(x) to be >= 0. I thought with increasing functions f'(x) is > 0?
[tex] \dfrac{(x^2 + 3)}{4x + 1} = f(x) [/tex]
[tex] \dfrac{(4x-6)(x+2)}{(4x+1)^2} = f'(x) [/tex] so setting this to be greater than zero I get the values of x < -2, and x > 2/3 however in the answers they got x <= -2 and x >= 2/3, and they set f'(x) to be >= 0. I thought with increasing functions f'(x) is > 0?