(Solved): \[ f(x)=x \sqrt{x^{2}+25} \] defined on the interval \( [-6,6] \). a.) \( f(x ...

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\[ f(x)=x \sqrt{x^{2}+25} \] defined on the interval \( [-6,6] \). a.) \( f(x) \) is concave down on the open interval b.) \( f(x) \) is concave up on the open interval c.) The minimum for this function occurs at d.) The maximum for this function occurs at Note: Your answer to parts \( \mathbf{a} \) and \( \mathbf{b} \) must be given in interval notation....