Cấp số nhân !!

A.q=−4.     

B.q=4.

C..q=−12.

D.q=10.

A.\[{u_3} = 12.\,\,\,\,\]

B. \[{u_3} = - 12.\]

C. \[{u_3} = 16.\]

D. \[{u_3} = - 16.\]

A.\[{S_5} = - 512\]

B. \[{u_5} = 256\]

C. \[{u_5} = - 512\]

D. \[q = 4\]

A.số hạng thứ 103       

B.số hạng thứ 104          

C.số hạng thứ 105         

D.Đáp án khác

A.\[{u_n} = {5^n}\]

B. \[{u_n} = {\left( {2 - \sqrt 3 } \right)^{n + 1}}\]

C. \[{u_n} = 5n + 1\]

D. \[{u_n} = {4^n}\]

A.\[{u_1} = - \frac{8}{3};q = \frac{3}{2}\]

B. \[{u_1} = \frac{8}{3};q = \frac{3}{2}\]

C. \[{u_1} = - \frac{5}{3};q = \frac{3}{2}\]

D. \[{u_1} = \frac{5}{3};q = \frac{3}{2}\]

A.190⁰  

B.191⁰

C.192⁰  

D.193⁰

A.\[x = 3;y = 1\]

B.\[x = 3;y = 1\] hoặc \[x = - \frac{{16}}{{13}};y = - \frac{2}{3}\]

C.\[x = 3;y = 1\]hoặc \[x = \frac{{ - 6}}{{13}};y = - \frac{2}{{13}}\]

D.\[x = 3;y = 1\]hoặc \[x = - \frac{{16}}{3};y = \frac{2}{3}\]

A.1     

B.2     

C.−1  

D.−2

A.12  

B.13  

C.14  

D.15

A.3183624     

B.2343625

C.2343626     

D.2343627

A.\[\frac{{{{10}^{11}} - 100}}{{81}}\]

B. \[\frac{{{{10}^{10}} - 100}}{{81}}\]

C. \[\frac{{{{10}^9} - 100}}{{81}}\]

D. \[\frac{{{{10}^8} - 100}}{{81}}\]

A.\[\frac{{\left( {n + 1} \right){a^{n + 2}} - (n + 2){a^{n + 1}} + 1}}{{{{\left( {1 - a} \right)}^2}}}\]

B. \[\frac{{\left( {n + 1} \right){a^{n + 2}} + (n + 2){a^{n + 1}} + 1}}{{{{\left( {1 - a} \right)}^2}}}\]

C. \[\frac{{\left( {n + 1} \right){a^{n + 2}} - (n + 2){a^{n + 1}} - 1}}{{{{\left( {1 - a} \right)}^2}}}\]

D. \[\frac{{\left( {n + 1} \right){a^{n + 2}} + (n + 2){a^{n + 1}} - 1}}{{{{\left( {1 - a} \right)}^2}}}\]

A.\[{S_{10}} = - 511.\]

B. \[{S_{10}} = - 1025.\]

C. \[{S_{10}} = 1025.\]

D. \[{S_{10}} = 1023.\]

A.\[m = - 7.\]

B. \[m = 1.\]

C. \[m = - 1\] hoặc\[m = 7.\]

D. \[m = 1\]  hoặc\[m = - 7.\]

A.\[x = 14.\]

B. \[x = 32.\]

C. \[x = 64.\]

D. \[x = 68.\]

B. q = 4.

B. u₃ = −12.

B. u₅ = 256

B. u₇ = −12.

A. $u_1=-\frac{8}{3};q=\frac{3}{2}$

B. $u_1=\frac{8}{3};q=\frac{3}{2}$

C. $u_1=-\frac{5}{3};q=\frac{3}{2}$

D. $u_1=\frac{5}{3};q=\frac{3}{2}$

B. 191⁰

B. S₁₀ = −1025.

B. 13  

A. $\frac{{10}^{11}-100}{81}$

B. $\frac{{10}^{10}-100}{81}$

C. $\frac{{10}^9-100}{81}$

D. $\frac{{10}^8-100}{81}$

A. $\frac{\left(n+1\right)a^{n+2}-\left(n+2\right)a^{n+1}+1}{{\left(1-a\right)}^2}$

B. $\frac{\left(n+1\right)a^{n+2}+\left(n+2\right)a^{n+1}+1}{{\left(1-a\right)}^2}$

C. $\frac{\left(n+1\right)a^{n+2}-\left(n+2\right)a^{n+1}-1}{{\left(1-a\right)}^2}$

D. $\frac{\left(n+1\right)a^{n+2}+\left(n+2\right)a^{n+1}-1}{{\left(1-a\right)}^2}$

B. m = 1.