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Find all relative extrema of the function. Use the Second Derivative Test where applicable. (If an answer does not exist, enter DNE.) h(t) = t 4\\/t+ 9 relative maximum (t, y) = (|:| ) relative minimum (t, y) = ( \f1. Consider the following function. f(x) = cos(x) - sin(x),= (0, 2n) (a)Find the critical numbers of f, if any. (Enter your answers as a comma-separated list.) x = (b) Find the open intervals on which the function is increasing or decreasing. (Enter your answers using interval notation. If an answer does not exist, enter DNE.) Increasing |:| decreasing :I (c) Apply the First Derivative Test to identify all relative extremes. (If an answer does not exist, enter DNE.) relative minimum (x, y) (|:|) relative maximum (x, y) (:I) 2. Find the points of inflection of the graph of the function. (Order your answers from smallest to largest X, then from smallest to largest y. If an answer does not exist, enter DNE.) for) = 6x4 x2 (\"=(S) ME) Describe the concavity. (Enter your answers using interval notatlon. If an answer does not exist, enter DNE.) concave downward |:l