Chứng minh rằng với mọi số nguyên dương k" role="presentation" style="border:0px; direction:ltr; display:inline-block; float:none; font-size:16.38px; line-height:0; margin:0px; max-height:none; max-width:none; min-height:0px; min-width:0px; padding:1px 0px; position:relative; white-space:nowrap; word-spacing:normal; word-wrap:normal" class="MathJax_CHTML mjx-chtml">k${\displaystyle k}$ ; ta có đẳng thức :

$$\frac{1}{{\sin }^2\frac{\pi }{4k+2}}+\frac{1}{{\sin }^2\frac{3\pi }{4k+2}}+\frac{1}{{\sin }^2\frac{5\pi }{4k+2}}+\cdots +\frac{1}{{\sin }^2\frac{(2k-1)\pi }{4k+2}}=2k(k+1$$ 

Hàm số (x)" role="presentation" style="border:0px; direction:ltr; display:inline-block; float:none; font-size:18.72px; line-height:0; margin:0px; max-height:none; max-width:none; min-height:0px; min-width:0px; overflow-wrap:normal; padding:1px 0px; position:relative; white-space:nowrap; word-spacing:normal" class="MathJax_CHTML mjx-chtml">y=f(x)$y=f(x)$ được cho bởi công thức x2−5" role="presentation" style="border:0px; direction:ltr; display:inline-block; float:none; font-size:18.72px; line-height:0; margin:0px; max-height:none; max-width:none; min-height:0px; min-width:0px; overflow-wrap:normal; padding:1px 0px; position:relative; white-space:nowrap; word-spacing:normal" class="MathJax_CHTML mjx-chtml">f(x)=2x2−5$f\left(x\right)=2x^2-5$.

Hãy tính: (1);f(−2);f(0);f(2)." role="presentation" style="border:0px; direction:ltr; display:inline-table; float:none; font-size:18.72px; line-height:0; margin:0px; max-height:none; max-width:none; min-height:0px; min-width:0px; overflow-wrap:normal; padding:1px 0px; position:relative; white-space:nowrap; word-spacing:normal" class="MathJax_CHTML mjx-chtml">f(1);f(−2);f(0);f(2).

Tìm giá trị lớn nhất của biểu thức sau: $A=3-\left|2x+1\right|$

$Tìm\; nhanh\; lên\; nhá$phần thưởng 3 cái tk

Tìm x,y,z \(\in\) N*

x7+y11+z13=0,(946053)${\displaystyle \frac{x}{7}+\frac{y}{11}+\frac{z}{13}=0,(946053)}$

Cho hàm số x2−2" role="presentation" style="border:0px; direction:ltr; display:inline-table; float:none; font-family:arial,tahoma,helvetica,sans-serif; font-size:18.72px; line-height:0; margin:0px; max-height:none; max-width:none; min-height:0px; min-width:0px; overflow-wrap:normal; padding:1px 0px; position:relative; white-space:nowrap" class="MathJax_CHTML mjx-chtml">y=f(x)=x2−2$y=f\left(x\right)=x^2-2$ . Hãy tính: (2);f(1);f(0);f(−1);f(−2)" role="presentation" style="border:0px; direction:ltr; display:inline-block; float:none; font-family:arial,tahoma,helvetica,sans-serif; font-size:18.72px; line-height:0; margin:0px; max-height:none; max-width:none; min-height:0px; min-width:0px; overflow-wrap:normal; padding:1px 0px; position:relative; white-space:nowrap" class="MathJax_CHTML mjx-chtml">f(2) ;f(1) ;f(0) ;f(−1) ;f(−2)

Tìm GTNN của B=$\left|x-1\right|+\left|2x-4\right|+\left|3x-9\right|+\left|4x-16\right|+\left|5x-25\right|$

giải cả lời giải nhanh giùm mk với

Cho hình 56, trong đó //HK,AH//BK." role="presentation" style="border:0px; direction:ltr; display:inline-block; float:none; font-size:18.72px; line-height:0; margin:0px; max-height:none; max-width:none; min-height:0px; min-width:0px; overflow-wrap:normal; padding:1px 0px; position:relative; white-space:nowrap; word-spacing:normal" class="MathJax_CHTML mjx-chtml">AB//HK,AH//BK.$AB//HK,AH//BK.$ Chứng minh rằng $AB=HK,AH=BK.$

Bài 1: Tìm $x$, biết:

1024. a) |x−3|=5x+8" role="presentation" style="border:0px; box-sizing:inherit; direction:ltr; display:inline-block; float:none; font-size:18.4px; line-height:0; margin:0px; max-height:none; max-width:none; min-height:0px; min-width:0px; overflow-wrap:normal; padding:1px 0px; position:relative; white-space:nowrap; word-spacing:normal" class="MathJax_CHTML mjx-chtml">12−|x−3|=5x+8$12-|x-3|=5x+8$                                                                         
1025. b) (x+3)10=1024.1252.252" role="presentation" style="border:0px; box-sizing:inherit; direction:ltr; display:inline-table; float:none; font-size:18.4px; line-height:0; margin:0px; max-height:none; max-width:none; min-height:0px; min-width:0px; overflow-wrap:normal; padding:1px 0px; position:relative; white-space:nowrap; word-spacing:normal" class="MathJax_CHTML mjx-chtml">(√x+3)10=1024.1252.252${\left(\sqrt{x}+3\right)}^{10}={1024.125}^2{.25}^2$
1026. c) $\frac{3-0,2x}{5}=\frac{7}{15}+1,4x$                                         
1027. d) (6427)x=4.59.710−511.79359.4" role="presentation" style="border:0px; box-sizing:inherit; direction:ltr; display:inline-block; float:none; font-size:18.4px; line-height:0; margin:0px; max-height:none; max-width:none; min-height:0px; min-width:0px; overflow-wrap:normal; padding:1px 0px; position:relative; white-space:nowrap; word-spacing:normal" class="MathJax_CHTML mjx-chtml">(6427)x=4.59.710−511.79359.4

Bài 2: Tính

A = 123.1212.5−224.33752.114−302.115" role="presentation" style="border:0px; box-sizing:inherit; direction:ltr; display:inline-block; float:none; font-size:18.4px; line-height:0; margin:0px; max-height:none; max-width:none; min-height:0px; min-width:0px; overflow-wrap:normal; padding:1px 0px; position:relative; white-space:nowrap; word-spacing:normal" class="MathJax_CHTML mjx-chtml">123.1212.5−224.33752.114−302.115$\frac{{12}^3{.121}^2.5-{22}^4{.3}^3}{{75}^2{.11}^4-{30}^2{.11}^5}$

B = $5\frac{11}{18}+\left(4\frac{1}{5}-3\frac{2}{9}\right)-\left(13\frac{1}{15}-\frac{2}{3}+\frac{7}{18}\right)+\left(\frac{2}{3}.\sqrt{2}-\sqrt{\frac{8}{9}}\right)$

$Bài\; 3:\; Tìm\; x\; biết:$

1. a) |x−2|=|2x+1|" role="presentation" style="border:0px; box-sizing:inherit; direction:ltr; display:inline-block; float:none; font-size:18.4px; line-height:0; margin:0px; max-height:none; max-width:none; min-height:0px; min-width:0px; overflow-wrap:normal; padding:1px 0px; position:relative; white-space:nowrap; word-spacing:normal" class="MathJax_CHTML mjx-chtml">|x−2|=|2x+1|$|x-2|=|2x+1|$                                                                       
2. b) $3\left(x+\frac{1}{2}\right)-\frac{1}{2}\left(4x-\frac{2}{3}\right)=\frac{5}{6}$
3. c) $\frac{7x+1}{4}=\frac{2x-9}{3}$

$1\frac{4}{23}+\frac{5}{21}-\frac{4}{23}+0,5+\frac{16}{21}$

$\sqrt{\frac{25}{81}}:2\frac{2}{5}-4\frac{5}{9}:2\frac{2}{5}$

$6.{\left(-\frac{-1}{2}\right)}^2+\frac{3}{5}$

$1\frac{4}{23}+\frac{5}{21}-\frac{4}{23}+0,5+\frac{16}{21}$

$\sqrt{\frac{25}{81}}:2\frac{2}{5}-4\frac{5}{9}:2\frac{2}{5}$

$6.{\left(-\frac{-1}{2}\right)}^2+\frac{3}{5}$