Question Number 985 by tera last updated on 13/May/15
$${jika}\:{fungsi}\:{f}\left({x}\right)=\:{px}^{\mathrm{2}} −\left({p}+\mathrm{1}\right){x}−\mathrm{6} \\ $$$${mencapai}\:{nilai}\:{tertingi}\:{untuk}\: \\ $$$${x}=−\mathrm{1}.\:{maka}\:{nilai}\:{p}=.....\mho \\ $$$$ \\ $$
Answered by prakash jain last updated on 13/May/15
$${f}\:'\left({x}\right)=\mathrm{2}{px}−\left({p}+\mathrm{1}\right),\:{f}\:''\left({x}\right)=\mathrm{2}{p} \\ $$$${f}\:'\left(−\mathrm{1}\right)=\mathrm{0}\Rightarrow−\mathrm{2}{p}−{p}−\mathrm{1}=\mathrm{0}\Rightarrow{p}=−\frac{\mathrm{1}}{\mathrm{3}} \\ $$$$\mathrm{If}\:{p}=−\frac{\mathrm{1}}{\mathrm{3}},\:{f}\:'\left(−\mathrm{1}\right)=\mathrm{0},\:{f}\:''\left(−\mathrm{1}\right)=−\frac{\mathrm{2}}{\mathrm{3}}<\mathrm{0} \\ $$