Describe a Scientific Calculator

Definition and function: A scientific calculator is a hand-held electronic device that performs arithmetic operations as well as scientific and engineering calculations such as trigonometric, logarithmic, exponential, power/root, statistical and fraction calculations. It is widely used by engineering students in examinations and laboratories.

Labelled diagram:

 +-------------------------------+
 | (1) Brand / model  (2) Solar  |
 |                       panel   |
 | +---------------------------+ |
 | | (3) LCD display (2 lines) | |
 | +---------------------------+ |
 | (4) SHIFT  ALPHA  [REPLAY]  MODE  ON |
 | (5) Function keys: x^-1 sqrt x^2 ^ log ln |
 |                    sin cos tan  (  )      |
 | (6) Memory keys: STO RCL M+              |
 | (7) Number keys 0-9, . , EXP, Ans        |
 | (8) DEL  AC                              |
 | (9) Operator keys + - x /    (10) =      |
 +-------------------------------+

Description of parts:

1. Casing: a rectangular plastic body, about 16 cm × 8 cm, usually with a sliding protective cover.
2. Power source: a small solar panel plus a button cell battery.
3. Display (LCD): a two-line liquid crystal display that shows the input expression on the upper line and the result on the lower line, along with status indicators (DEG/RAD, S, A, M).
4. Control keys: ON, SHIFT (activates the second function printed above a key), ALPHA (variables), MODE/SETUP (selects calculation mode, angle unit, number format) and the REPLAY/cursor pad for editing.
5. Function keys: sin, cos, tan, log, ln, x², √, xʸ, x⁻¹, factorial, fraction, brackets etc. for scientific calculations.
6. Memory keys: STO, RCL, M+ and Ans to store and recall values.
7. Number keys: 0–9, decimal point and EXP (×10ⁿ) for entering numbers.
8. Arithmetic operator keys: +, −, ×, ÷ and the = key that gives the result.
9. DEL and AC keys: DEL deletes the last character; AC clears the whole entry.

Working (in brief): Switch on with ON, select the required mode with MODE, enter the expression using number, function and operator keys, and press = to see the result on the display.