Question

How do I do geometric sequences on an Nspire?

Answer 1

Hint: Nspire is a graphic calculator that is a robust and hands-on learning tool. The calculator enables us to use images for a better understanding of mathematical problems using graphs and figures. We can do geometric sequences on a Nspire as follows, Menu > Statistics > List Math > Sequence.

Complete answer:
The Nspire is the thinnest technology integration graphical calculator. Its features include high resolution, full- color display etc. The high resolution of the calculator helps us to see every exponent, variable, and line.
The graphical calculator supports a teaching strategy that helps in a better understanding of complex mathematical equations and scientific problems.
It helps to visualize the graphical, algebraic, geometric expressions by presenting them simultaneously.
The calculator comes with integrated mathematics templates that help us to view the mathematical formulae, symbols just as printed in the textbook.
The following steps are to be followed to do a geometric sequence on Nspire:
1. Press the menu button on the graphic calculator.
2. Select statistics from the drop-down menu.
3. Click on the List Math option displayed on the screen.
4. Click on the sequence to start writing a sequence.
The above steps can be summarised as
$\Rightarrow$Menu > Statistics > List Math > Sequence
Example:
Let S = 1+2+4+8…. be a geometric sequence.
We have to find the least value of n for which ${{S}_{n}}>100$.
The value of ${{S}_{n}}$is given by
$\Rightarrow {{S}_{n}}=\dfrac{1\left( {{\left( 2 \right)}^{x}}-1 \right)}{\left( 2-1 \right)}$
$\therefore {{S}_{n}}=\left( {{\left( 2 \right)}^{x}}-1 \right)$
We should type the value of ${{S}_{n}}$in the calculator as,
$\Rightarrow f\left( x \right)=\left( {{\left( 2 \right)}^{x}}-1 \right)$
Now,
From the scratchpad option displayed, we can choose a graph to be plotted for the above function.
Then, we need to click on the split screen option to get the values of $f\left( x \right)$ for different values of $x$.
From the table, we can easily choose the least value of n for which ${{S}_{n}}>100$.

Note: A Nspire calculator helps us to symbolically solve equations. The calculator can easily be used to find the derivatives and compute the value of limits. Matrix operations such as transpose, augmented, inverse, determinant can be easily performed in the calculator