The weekly profit P for a widget producer is a function of the number n of widgets sold. The formula is as follows, where P is measured in thousands of dollars, n is measured in thousands of widgets, and the formula is valid up to a level of 4 thousand widgets sold. P = −2 + 2.1n − 0.4n2
At what sales level is the profit as large as possible? (Use the graph to find the value. Round your answer to the nearest whole number.)
n = ______thousand widgets?