1. If \( y=3 t^{4}-\operatorname{tand} x=e^{-t^{2}} \), compute \( \left.\frac{d y}{d x}\right|_{t=0} \) 2. If \( y=3 t^{-2} \) and \( x=e^{-3 t} \), compute \( \left.\frac{d y}{d x}\right|_{t=0} \)

A particle \( P \) moves in a straight line so that, \( t \) seconds after passing a fixed point \( O \), its displacement, \( s \) metres, is given by \( s=4 t^{3}-15 t^{2}+18 t \). Find (i) the velocity of \( P \) when \( t=3 \), (ii) the acceleration of \( P \) when \( t=3 \), (iii) the values of \( t \) when \( P \) is at instantaneous rest, (iv) the distance travelled by \( P \) in the first 2 seconds of its motion, (v) the distance of \( P \) from \( O \) when \( t=2 \).

4) \( \lim _{x \rightarrow 0} \frac{2 x+5 x^{-2}}{3 x+x^{-2}}= \)

3. Given \( T P=90 \mathrm{~K}^{2}-\mathrm{K}^{3} \) find a. Marginal product b. Average product c. The value of output which equates average product and marginal product

c. The value of output which equates average product and marginal product Use the product rule to find the first-order partials for each of the following functions a. \( z=3 x^{2}(5 x+7 y) \) b. \( z=(9 x-4 y)(12 x+2 y) \)

Find the volume of the solid formed by rotating the area under the curve \( y = \frac{1}{x} \) from \( x = 1 \) to \( x = 3 \) about the y-axis.