A t-shirt manufacturer is planning to expand its workforce. it estimates that the number of t-shirts produced by hiring x new workers is given by t(x)=−0.25x^4+9x^3 0≤x≤27 when is the rate of change of t-shirt production increasing and when is it decreasing? what is the point of diminishing returns and the maximum rate of change for t-shirt production? graph t and t′ on the same coordinate system.