Answer all, please

1. Consider a triangle with base a: and height 211*. Find the instantaneous rate of change of the area of the triangle with respect too: when :t: = 5. 3. Supposethe cost C(q] (in dollars} of producing a quantity. 1.}. of a product is given by _ l 0 City} = 000 - 3g - mg\" The marginal cost. I'lIqu}. equals the instantaneous rate of change of the cost with respect to the quantity. Find the marginal cost when a quantity.r of 25 items is being produced. 4. LetR[t} be the number of centimetres of water that has fallen since midnight. wheret is measured in hours. Interpret the following. a. 3(9) = 2.5 new) = 0.2 100 5. If the cost. C {in cents). of purifying a litre of water to a purity of 11 percent is C(11) = W for 50 g n