A 2 rn ladder leans against a wall. If the base slides out at a rate Df 0.8 misee. then how fast is the area of the triangle underneath the ladder changing at the instant when the base of the ladder is l m from the wall? Let's start by dening variables, and translate these words into something we can werlc with! Let: denote the distance from the base of the ladder to the wall, 1? denote the time in seconds. and A denote the area at the triangle under the ladder. We are told that We need to nd a fennula ferA in tenne ef the verieblex: Using eur predigieue skill at differentiating dd _ a (1) _ | 1% m; WEE:- dA_dAabc Se by the chain rule E E E we deduce that at the time In queetlen : " d: ' g % mfeee