Question

[Pham Trong Bach]

$\left(d_1\right):\left\{\begin{array}{l}x=1-t\\ y=t\\ z=4t\end{array}\right.$ , $\frac{x-1}{2}=\frac{y+1}{-1}=z$, $\frac{5}{12}$, $y=\frac{2x+1}{x+2}$,  $m=\pm 3$,  $z=x+yi$,  $\left|\frac{z-3}{z-1+2i}\right|$,  $\left[z\left(1-i\right)+\stackrel{-}{z}\left(1+i\right)\right]$,, $A=a^2-b^2$

$V=\frac{1}{3}Bh$,  $y=f\left(x\right)$,  $V=\mathrm{\pi }\left(\frac{5}{3}-2\ln 2\right)$,  $T=a+b$,  $\left|z_1-z_2\right|$,  $\frac{z_2-z_1}{1+i}$,  $\frac{3\left(2-\sqrt[3]{4}\right)}{4}$,  $\cos 2\alpha =-\frac{4}{5}$

$S={\int }_a^{b}f\left(x\right)dx$,  $S=\mathrm{\pi }{\int }_a^b{f}^2\left(x\right)dx$,  $S=1+{\log }_3\frac{2}{5}$,  $S=1+\ln \frac{2}{5}$,  $\underset{\left[0;1\right]}{\max }\left|f\left(x\right)\right|= 6$,  $y=\frac{m \cos x+1}{\cos x+m}$

$y=2{\sin }^2 x+3\sin 2x-4{\cos }^{2}x$,  ${\mathrm{C}}_{\mathrm{n}+4}^{\mathrm{n}+1}-{\mathrm{C}}_{\mathrm{n}+3}^{\mathrm{n}}=7\left(\mathrm{n}+3\right)$, $\mathrm{y}=\frac{1}{\sqrt{{\displaystyle \frac{1}{{\log }_{{\displaystyle \frac{1}{3}}}\left(x^2-4x+6\right)}}+{\displaystyle \frac{1}{2}}}}$,  $\frac{1}{a},\frac{1}{b},\frac{1}{c}$

$A\left(-1;-1;1\right)$,  $\mathrm{y}={\mathrm{x}}^3-6{\mathrm{x}}^2+9\mathrm{x}-2$ ,  $\left(P\right): 2\mathrm{x}-2y+z+5=0$,  $\left(P\right)$,  $4z^2-4z+3=0$ ,   $z_1, z_2$,  $d_1, d_2,d_3$,  $\mathrm{S}=9+99+999+...+\underset{\mathrm{n} \mathrm{so} 9}{\underset{⏟}{99...99}}$

${\mathrm{A}}_1{\mathrm{B}}_1{\mathrm{C}}_1{\mathrm{D}}_1$,  $\left(d_1\right):\left\{\begin{array}{l}x+y-1=0\\ 2x+z=0\end{array}\right.$,  $\left\{\begin{array}{l}{2}^x.9^y=36\\ 3^x.4^y=36\end{array}\right.$

$\stackrel{\rightharpoonup }{n}=\left(2;-2;1\right)$,  ${\log }_2\left(\mathrm{x}+1\right)<1$,    ,  ${\int }_0^1\left(3x^2+1\right)dx$,  ${\int }_0^{1}f\text{'}\text{'}\left(x\right)\left(1-x\right)dx=1$,  $\mathrm{y}=-{\left|\mathrm{x}\right|}^3+3\left|\mathrm{x}\right|$, $m<\frac{1}{2}$

Answer 1

[Cao Minh Tâm]

a ∈ ( 0 ; π 2 ] ,  c o t α 2 ,  c o s   α 2 sin 2 α + sin   α - 3 = 0 , 2 πa 3 ; 4 πa 2 B S C ^ = 30 ° ,   A S B ^ = 60 ° ,  60 ° ,  a 42 7 , a 3 3 , u ⇀ = m a ⇀ - 3 b ⇀ , α