Mọi người giúp em vs ạ Question Mọi người giúp em vs ạ in progress 0 Môn Toán RI SƠ 5 years 2021-04-20T05:35:59+00:00 2021-04-20T05:35:59+00:00 1 Answers 18 views 0
Answers ( )
Đáp án:
$\begin{array}{l}
1)a)y = {x^4} + 3{x^2} + 2x\\
\Leftrightarrow y’ = 4{x^3} + 6x + 2\\
b)y = \dfrac{{x – 1}}{{3x + 1}}\\
\Leftrightarrow y’ = \dfrac{{1.\left( {3x + 1} \right) – 3.\left( {x – 1} \right)}}{{{{\left( {3x + 1} \right)}^2}}}\\
= \dfrac{{3x + 1 – 3x + 3}}{{{{\left( {3x + 1} \right)}^2}}}\\
= \dfrac{4}{{{{\left( {3x + 1} \right)}^2}}}\\
c)y = x.\tan x\\
\Leftrightarrow y’ = \tan x + x.\dfrac{1}{{{{\cos }^2}x}}\\
2)a)y = 2{x^3}\\
\Leftrightarrow y’ = 6{x^2}\\
PTTT:y = {y_o}’\left( {x – {x_0}} \right) + {y_0}\\
+ Khi:M\left( { – 1; – 1} \right)\\
\Leftrightarrow {x_0} = – 1;{y_0} = – 1\\
\Leftrightarrow PTTT:y = 6.{\left( { – 1} \right)^2}\left( {x + 1} \right) – 1\\
\Leftrightarrow y = 6x + 5\\
b)HSG:{y_0}’ = 6\\
\Leftrightarrow 6x_0^2 = 6\\
\Leftrightarrow {x_0} = 1/{x_0} = – 1\\
\Leftrightarrow \left[ \begin{array}{l}
PTTT:y = 6\left( {x – 1} \right) + {2.1^3}\\
PTTT:y = 6x + 5
\end{array} \right.\\
\Leftrightarrow \left[ \begin{array}{l}
PTTT:y = 6x – 4\\
PTTT:y = 6x + 5
\end{array} \right.
\end{array}$