Show all your work The law of diminish returns in economics is related to the idea of concavity. If the input were advertising costs for some product, the output might be the corresponding revenue from sales. The inflection point (c, f(c)) is called the point of diminishing returns. The revenue generated from sales of a toy is related to the amount x spent of advertising by: Where x and R(x) are in thousands of dollars. Is there a point of diminishing returns for this function? If so what is it is? Explain what your answer means