1.11 Electronic Calculators

Modes/setups

Modes/setups

• Angle Units should be in Degrees (D) or Radians (R), you can choose the set up by pressing Shift + Mode/Setup

• When in “Math” mode (written on top-right corner of calculator), you can press the “S ↔ D” button to switch between the exact (e.g. pi, surds, fractions, etc) and approximate (decimal approximation) values.

Template shrotcuts

Abs → for absolute value

x^3 → for cubing a number

x^-1 → for finding a number’s reciprocal

log _ _ → for writing a log expression

fraction button → for writing fractions

square root button → for finding a number’s square root

x^2 button → for finding a number’s square

x^_ → for writing a number to a specified power

log → for writing logarithms in base 10

ln → log base e

S ↔ D → switch between exact and approximate values

Shift + x^-1 → x! → finding a number’s factorial

Shift + fraction button → mixed number button

Shift + square root button → finding a number’s cube root

Shift + x^_ button → finding a number’s nth root

Shift + log → specifying a power of 10

Shift + ln → specifying a power of e

Shift + S ↔ D → switch between mixed numbers and improper fractions

Trigonometry

sin

cos

tan

Shift + sin → sin^-1 → inverse of sine

Shift + cos → cos^-1 → inverse of cosine

Shift + tan → tan^-1 → inverse of tangent

Write the angles inside the brackets of these trigonometric functions, ensure you CLOSE THE BRACKET because the calculator only automatically gives you the open bracket.

Standard Form and π

x 10^x → standard form

Shift + x 10^x → π

Memory and previous answer

ANS button lets you recall the previous/last answer calculated by the calculator.

This is especially useful for when you are doing a question involving decimals, because you should NOT round too early, ONLY round at the end of ALL calculations when you obtain the FINAL answer.

Tables

1. Press “Mode/Setup”.

2. Press 3 to get table mode.

3. Write in equation after “f(x) =” (This equation shows the relationship between x and y).

   1. If you want to write y = 2x + 19, it’s the same as f(x) = 2x + 19, press ALPHA + ) to get the X character or ALPHA + S ↔ D to get the y character.

4. Type in a starting value, then press the = button.

5. Type in an ending value, then press the = button.

6. Type in a step value (i.e. interval or common difference), then press the = button.

7. Table of values will be generated for you.

8. You can use the arrow keys to navigate up/down the rows of the table to find the relevant answer.

9. This is especially useful for types of question where they ask you: “complete the table of values and draw a graph”.

10. If you want to go back to the calculator’s normal computing mode, press Mode/Setup and press the number 1 to enter the COMP mode.

Negative numbers

Use the (-) button instead of the - (subtract) button for negative numbers, though both should work fine.

Judgement & Special Features

If a question asks you to write down all the digits on your calculator display, do so.

It is better to write too many digits than not have enough, and this is especially useful for finding suitable answers when comparing upper/lower bounds of a value.

What should you do when squaring a negative number, or raising a negative number to an even power?

When raising a negative number to an even power, remember to write the negative number in brackets, then raise the bracketed expression to an even power.

E.g: -3^4 is DIFFERENT from (-3)^4 because -3^4 = -81 while (-3)^4 will evaluate to 81.

What should you do when the final answer needs to be rounded?

In working out, never round mid-stage answers from calculations (that are not final answers).

Always write more digits than the final answer requires in working out and DO NOT ROUND it, you can use 3 dots to show you haven’t rounded something. E.g: 9.9999999…

Use the ANS button when you next need that unrounded answer in your calculation.

ONLY ROUND to the necessary degree of accuracy AFTER you have obtained your FINAL result once ALL calculations have been completed.