# Math Help - sequences

1. ## sequences

determine t3,t5,and t10 for the sequences

a) tn=(2n-1)squared
b) tn=3n-1-2
c) tn= (n-1)/(2n-1)

2. Originally Posted by euclid2
determine t3,t5,and t10 for the sequences

a) tn=(2n-1)squared
Just substitute n=3, 5 and 10.

For example $t_{\color{red}5}=(2*{\color{red}5}-1)^2=(10-1)^2=81$

b) tn=3n-1-2
Are you sure it is this writing ? o.O

c) tn= (n-1)/(2n-1)
For example :
$t_{\color{red}3}=\frac{{\color{red}3}-1}{2*{\color{red}3}-1}=\frac{2}{6-1}=\frac 25$

Is it clear ?

3. For b, it is not written like that, the n-1 is small in the right hand corner as if an exponent

4. [quote=euclid2;186590]determine t3,t5,and t10 for the sequences

a) tn=(2n-1)squared

${\text{General term, }}t_n = \left( {2n - 1} \right)^2 \hfill \\$

${\text{Now, for }}t_3 {\text{ put }}n = 3, \hfill \\$

$
t_3 = \left( {2 \times 3 - 1} \right)^2 = 5^2 = 25 \hfill \\$

${\text{Now, for }}t_5 {\text{ put }}n = 5, \hfill \\$

$t_5 = \left( {2 \times 5 - 1} \right)^2 = 9^2 = 81 \hfill \\$

${\text{Now, for }}t_{10} {\text{ put }}n = 10, \hfill \\$

$t_{10} = \left( {2 \times 10 - 1} \right)^2 = 19^2 = 361 \hfill \\
$

5. Thanks, I'm unsure of how to do b) since there is the exponent n-1

6. Originally Posted by euclid2
For b, it is not written like that, the n-1 is small in the right hand corner as if an exponent
Please use ^ for an exponent

$b) ~t_n=3^{n-1}-2$ ?

$t_{10}=3^{10-1}-2=3^9-2=19681$

7. [quote=euclid2;186590]determine t3,t5,and t10 for the sequences

b) tn=3^{n-1} - 2

${\text{General term, }}t_n = 3^{n - 1} - 2 \hfill \\$

${\text{Now, for }}t_3 {\text{ put }}n = 3, \hfill \\$

$t_3 = 3^{3 - 1} - 2 = 3^2 - 2 = 9 - 2 = 7 \hfill \\$

${\text{Now, for }}t_5 {\text{ put }}n = 5, \hfill \\$

$t_5 = 3^{5 - 1} - 2 = 3^4 - 2 = 81 - 2 = 79 \hfill \\$

${\text{Now, for }}t_{10} {\text{ put }}n = 10, \hfill \\$

$t_{10} = 3^{10 - 1} - 2 = 3^9 - 2 = 19683 - 2 = 19681 \hfill \\
$