Giúp vs ạ , cảm ơn nhìu
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HP
29 tháng 7 2021
a, \(f\left(x\right)=2x^4-x^3+4x^2-x\)
\(\Rightarrow f'\left(x\right)=\left(2x^4-x^3+4x^2-x\right)'\)
\(=\left(2x^4\right)'-\left(x^3\right)'+\left(4x^2\right)'-\left(x\right)'\)
\(=2.4x^3-3x^2+4.2x-1\)
\(=8x^3-3x^2+8x-1\)
b, \(f\left(x\right)=2sinx\)
\(\Rightarrow f'\left(x\right)=\left(2sinx\right)'=2cosx\)
c, \(f\left(x\right)=\dfrac{3x^2+2x-5}{x}\)
\(\Rightarrow f'\left(x\right)=\left(\dfrac{3x^2+2x-5}{x}\right)'\)
\(=\left(3x+2-\dfrac{5}{x}\right)'\)
\(=\left(3x\right)'+\left(2\right)'-\left(\dfrac{5}{x}\right)'\)
\(=3+0+\dfrac{5}{x^2}=\dfrac{5}{x^2}+3\)
2 tháng 1 2022
1, The homework is too difficult for him to do
2, The homework isn't easy enough for him to do
3, The homework is so difficult that he can't do it
4, It is such difficult homework that he can't do it
DT
7 tháng 1 2022
1. My sister says she went to school by bus this morning.
My sister said she had gone to school by bus that morning.
2. Nga says she have done her homework.
Nga said she had done her homework.
7 tháng 1 2022
1, My sister says that she goes to school by bus this morning
My sister said that she had gone to school by bus this morning
2, Nga says that she have done her homework
Nga said that she had done her homework
PL
1
PL
30 tháng 8 2022
Bài 1: \(n_{CuO}=\dfrac{3,2}{80}=0,04\left(mol\right)\)
\(CuO+H_2SO_4\rightarrow CuSO_4+H_2O\)
0,04 → 0,04
\(\Rightarrow m_{H_2SO_4}=0,04\cdot98=3,92\left(g\right)\)
\(\Rightarrow C\%_{H_2SO_4}=\dfrac{3,92}{80}\cdot100\%=4,9\%\)
Bài 2: \(n_{HCl}=0,2\cdot2=0,4\left(mol\right)\)
\(Fe_2O_3+6HCl\rightarrow2FeCl_3+3H_2\uparrow\)
\(\dfrac{1}{15}\) ← 0,4
\(\Rightarrow m_{Fe_2O_3}=\dfrac{1}{15}\cdot160=\dfrac{32}{3}\left(g\right)\)
DT
24 tháng 12 2021
1.........................................
=>the computer hasn't been fixed by them yet
2.......................................
=>Last night I was helped by a stranger.
giúp mik vs ạ. Cảm ơn nhìu nhé
17 tháng 1 2022
\(PT\Leftrightarrow\left(3x+5\right)\dfrac{x+1}{2}+\left(3x+5\right)\dfrac{2x-2}{3}-\left(3x+5\right)=0\)
\(\Leftrightarrow\left(3x+5\right)\left(\dfrac{x+1}{2}+\dfrac{2x-2}{3}-1\right)=0\)
\(\Leftrightarrow\left(3x+5\right)\dfrac{3\left(x+1\right)+2\left(2x-2\right)-6}{6}=0\)
\(\Leftrightarrow\left(3x+5\right)\dfrac{7x-7}{6}=0\)
\(\Leftrightarrow\left(3x+5\right)\left(x-1\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{-5}{3}\\x=1\end{matrix}\right.\)
KL: Phương trình có tập nghiệm \(S=\left\{\dfrac{-5}{3};1\right\}\)
23 tháng 10 2023
3: \(\left(\dfrac{1}{\sqrt{2}-1}-\dfrac{1}{\sqrt{2}+1}\right):\sqrt{3-2\sqrt{2}}\)
\(=\dfrac{\sqrt{2}+1-\sqrt{2}+1}{2-1}:\left(\sqrt{2}-1\right)\)
\(=\dfrac{2}{\sqrt{2}-1}=2\left(\sqrt{2}+1\right)=2\sqrt{2}+2\)
5:
\(\dfrac{\sqrt{5}+\sqrt{3}}{\sqrt{5}-\sqrt{3}}+\dfrac{\sqrt{5}-\sqrt{3}}{\sqrt{5}+\sqrt{3}}\)
\(=\dfrac{\left(\sqrt{5}+\sqrt{3}\right)^2+\left(\sqrt{5}-\sqrt{3}\right)^2}{\left(\sqrt{5}-\sqrt{3}\right)\left(\sqrt{5}+\sqrt{3}\right)}\)
\(=\dfrac{8+2\sqrt{15}+8-2\sqrt{15}}{2}=\dfrac{16}{2}=8\)
6:
\(\dfrac{\sqrt{5}-1}{\sqrt{5}+1}-\dfrac{\sqrt{5}+1}{\sqrt{5}-1}\)
\(=\dfrac{\left(\sqrt{5}-1\right)^2-\left(\sqrt{5}+1\right)^2}{\left(\sqrt{5}+1\right)\left(\sqrt{5}-1\right)}\)
\(=\dfrac{6-2\sqrt{5}-6-2\sqrt{5}}{4}=\dfrac{-4\sqrt{5}}{4}=-\sqrt{5}\)
4:
\(\dfrac{6}{\sqrt{2}-\sqrt{3}+3}\)
\(=\dfrac{6\left(\sqrt{2}-\sqrt{3}-3\right)}{\left(\sqrt{2}-\sqrt{3}-3\right)\left(\sqrt{2}-\sqrt{3}+3\right)}\)
\(=\dfrac{6\left(\sqrt{2}-\sqrt{3}-3\right)}{5-2\sqrt{6}-9}=\dfrac{-6\left(\sqrt{2}-\sqrt{3}-3\right)}{4+2\sqrt{6}}\)
\(=\dfrac{-3\left(\sqrt{2}-\sqrt{3}-3\right)}{\sqrt{6}+2}=\dfrac{-3\left(\sqrt{2}-\sqrt{3}-3\right)\left(\sqrt{6}-2\right)}{2}\)
\(=\dfrac{-3\left(2\sqrt{3}-2\sqrt{2}-3\sqrt{2}+2\sqrt{3}-6\sqrt{3}+6\right)}{2}\)
\(=\dfrac{-3\left(-2\sqrt{3}-5\sqrt{2}+6\right)}{2}\)
a) \(=5x\left(y+2x\right)\)
b) \(=x\left(x-6y\right)+3\left(x-6y\right)=\left(x-6y\right)\left(x+3\right)\)
c) \(=\left(x^2+6x+9\right)-y^2=\left(x+3\right)^2-y^2=\left(x-y+3\right)\left(x+y+3\right)\)
d) \(=\left(x^2-5x\right)-\left(4x-20\right)=x\left(x-5\right)-4\left(x-5\right)=\left(x-4\right)\left(x-5\right)\)
a) 5x( y+ 2)
b)(x2+3x)-(6xy+ 18y)
=x(x+3)-6y(x+3)
=(x+3)(x-6y)
c)(x2-y2)+ (6x+9)
=(x-y)(x+y)+3(2x+3)
d) chịu nha