Question

Найдите точку максимума функции y = ln(x + 15)^16 - 16x

Answer 1

$y=ln(x+15)^{16}-16x=16\cdot ln(x+15)+16x\; \; ,\; \; ODZ:\; x>-15\\\\y'=16\cdot \frac{1}{x+15}-16=16\cdot (\frac{1}{x+15}-1)=0\; \; \Rightarrow \frac{1}{x+15}-1=0\\\\\frac{1-x-15}{x+15}=0\; \; \Rightarrow \; \; -x-14=0\; ,\; x\ne -15\\\\x=-14\; \; \; \; kriticheskaya\; (stacionanaya)\; tochka\\\\znaki\; y':\; \; \; ---(-15)+++(-14)---\\\\y(x):\; \quad \qquad \; \; \; (-15) \; \; \nearrow \; \; (-14)\; \; \searrow \\\\\underline {x_{max}=-14}\\\\y_{max}=ln(-14+15)^{16}-16\cdot (-14)=\underbrace {ln1}_{0}+224=224$