![\bf f(x)=(x-6)e^{-3x}\\\\ -----------------------------\\\\ \cfrac{dy}{dx}=1\cdot e^{-3x}+(x-6)-3e^{-3x}\implies \cfrac{dy}{dx}=e^{-3x}[1-3(x-6)] \\\\\\ \cfrac{dy}{dx}=e^{-3x}(19-3x)\implies \cfrac{dy}{dx}=\cfrac{19-3x}{e^{3x}}](https://tex.z-dn.net/?f=%5Cbf%20f%28x%29%3D%28x-6%29e%5E%7B-3x%7D%5C%5C%5C%5C%0A-----------------------------%5C%5C%5C%5C%0A%5Ccfrac%7Bdy%7D%7Bdx%7D%3D1%5Ccdot%20e%5E%7B-3x%7D%2B%28x-6%29-3e%5E%7B-3x%7D%5Cimplies%20%5Ccfrac%7Bdy%7D%7Bdx%7D%3De%5E%7B-3x%7D%5B1-3%28x-6%29%5D%0A%5C%5C%5C%5C%5C%5C%0A%5Ccfrac%7Bdy%7D%7Bdx%7D%3De%5E%7B-3x%7D%2819-3x%29%5Cimplies%20%5Ccfrac%7Bdy%7D%7Bdx%7D%3D%5Ccfrac%7B19-3x%7D%7Be%5E%7B3x%7D%7D)
set the derivative to 0, solve for "x" to get any critical points
keep in mind, setting the denominator to 0, also gives us critical points, however, in this case, the denominator will never be 0, so... no critical points from there
there's only 1 critical point anyway, and do a first-derivative test on it, check a number before it and after it, to see what sign the derivative has, and thus, whether the graph is going up or down, to check for any extrema
Yes.
8 + 1 + 1 = 10, so there are 10 parts to the ratio.
3.5 litres divided by 10 would mean that each part of the ratio is worth 0.35 litres.
The colour is worth 8 parts of the ratio. 0.35 litres multiplied by 8 would give 2.8 litres, meaning 2.8 litres of colour are required.
Fiona has 2.9 litres of colour, which is more than enough to make 3.5 litres of paint mix.
Assume ladder length is 14 ft and that the top end of the ladder is 5 feet above the ground.
Find the distance the bottom of the ladder is from the base of the wall.
Picture a right triangle with hypotenuse 14 feet and that the side opposite the angle is h. Then sin theta = h / 14, or theta = arcsin 5/14. theta is
0.365 radian. Then the dist. of the bot. of the lad. from the base of the wall is
14cos theta = 14cos 0.365 rad = 13.08 feet. This does not seem reasonable; the ladder would fall if it were already that close to the ground.
Ensure that y ou have copied this problem accurately from the original.
