The profit, in thousands of dollars, from the sale of x thousand mechanical pencils, can be estimated by 𝑃 ( 𝑥 ) = 2 𝑥 − 0.2 𝑥 𝑙 𝑛 𝑥 Find the rate at which the profit is changing when 120 thousand pencils have been sold ( 𝑃 ′ ( 120 ) ). Round to THREE decimal places and then enter decimals without units and symbols. Example: If the answer is 0.123 thousand dollars per 1000 pencils, then enter 0.123 as your answer. If the answer is -0.123 thousand dollars per 1000 pencils, then enter -0.123 as your answer.简答题