Arithmetic in Matlab

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Misc

Introductions

Nicole Tomei, observer and occasional helper.

Math Learning Center Opens Today

M - F mid-day plus M - R evenings; see https://www.geneseo.edu/math/mlc for details

Colloquium

Friday January 27, 3:00 PM, Newton 203

Prof. Aguilar on Google’s Page Rank algorithm, a key part of how Google decides what pages to list first when you do a search, and being a neat application of linear algebra.

Extra credit for attending and writing me a roughly 1-paragraph summary of some connection(s) you made between the talk and your own interests, experience, ideas, etc. Only “due date” is that you give me the summary before our final exam in May.

Questions?

Arithmetic in Matlab

Built-in operations

Video tutorial

Example: Two hypothetical investments, one for a fixed term of 1 year at 1.3% interest per year, and one for a fixed term of 2 years at 1.5% per year. Note that if interest rates rise over the next year, you could do better investing at the lower rate now and then reinvesting the money at a higher rate in a year. Use Matlab to compute the minimum interest rate 1 year from now that would make this strategy better than investing now in the 2-year investment.

What from the video is relevant?

• Matlab can act like a calculator to do arithmetic
• Uses * for multiplication and / for division and ^ for exponentiation
• Uses conventional order of operations and parentheses
• But converts fractions to decimal
• Use format command to control how many digits you see

Solution ideas

• First figure out calculation (algorithm)
  • a = p(1+r)^t or, for reinvestment a = p(1+r₁)(1+r₂)
  • Two-year: r = 0.015, t = 2
  • Reinvesting: r₁ = 0.013, r₂ = ?
• Then write code

Here are the commands we ended up using:

>> (1+0.015)^2
ans =
    1.0302
>> % Solve (1+0.015)^2 < (1+0.013)(1+r)
>> ((1+0.015)^2 / (1+0.013)) - 1
ans =
    0.0170

Built-in functions

Some examples

>> sin( 3.14159 )
ans =
    2.6536e-06
>> sin( 3.14159 / 2 )
ans =
    1.0000

Next

Defining your own functions in Matlab

Watch this video introduction (or at https://www.youtube.com/watch?v=QYOUq2KI1uo)

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