Quick facts
- •sin(30) is 0.5 in degree mode but about −0.988 in radian mode. Most "wrong" trig answers come from the wrong mode.
- •log is base 10 and ln is base e. log(100) is 2, and ln(100) is about 4.605.
- •A full circle is 360° or 2π radians. To convert degrees to radians, multiply by π ÷ 180.
- •Order of operations applies: 2 + 3 × 4 is 14, not 20. Brackets change the order when you need them to.
- •Typing 3.14 instead of π introduces an error of about 0.05%, which can matter in long calculations.
Quick reference
| Function | What it does | Common mistake |
|---|---|---|
| sin, cos, tan | Trigonometric ratios of an angle | Wrong DEG/RAD mode |
| log | Logarithm to base 10 | Used instead of ln |
| ln | Natural logarithm, base e | Used instead of log |
| √ | Square root | Used when a cube root is needed |
| π | Pi, about 3.14159 | Typing 3.14 instead |
Worked examples
What is sin(45°) in degree mode?
0.7071, which equals √2 ÷ 2
In radian mode, sin(45) is about 0.851, which is a different number. Check the mode indicator before you type.
What is the natural log of 100?
4.6052
ln(100) is the power you raise e to in order to get 100. log(100) is 2, because 10² = 100.
What is 2 + 3 × 4?
14, not 20
Multiplication comes before addition. To add first, write (2 + 3) × 4, which gives 20.
What is the pH of a solution with [H⁺] = 1 × 10⁻⁴ mol/L?
pH = 4
pH = −log[H⁺]. The base-10 log of 10⁻⁴ is −4, so pH = 4. Using ln here would give about 9.21, which is wrong.
How do I convert 180° to radians?
π, which is about 3.1416
Multiply by π ÷ 180. For 180° that gives π. To go the other way, multiply radians by 180 ÷ π.
Not checking DEG or RAD
The mistake
Entering a trig problem without checking whether the calculator is in degrees or radians. sin(30) is 0.5 in degrees and about −0.988 in radians.
Do this instead
Check the mode before every trig problem. If the answer is off by a factor of about 57.3, the mode is probably wrong.
Why it matters
Every step after the first is built on the wrong value, so a whole answer can be wrong even when your method is right.
Why a scientific calculator matters
Check the DEG/RAD mode first
- •Degrees and radians are two units for the same angle, and the calculator treats them differently.
- •The wrong mode gives a believable number, which is why mistakes slip through.
- •If your answer is off by a factor of about 57.3, which is 180 ÷ π, the mode is the likely cause.
- •Look at the mode indicator before every trig problem.
log or ln?
- •log is base 10 and is used for pH, decibels and the Richter scale.
- •ln is base e and is used for growth, decay and half-life problems.
- •log(100) = 2 but ln(100) ≈ 4.605, so using the wrong key changes the answer.
- •Read the question and check which log it asks for.
Use memory for long problems
- •M+ adds the shown value to memory, MR recalls it and MC clears it.
- •Storing an intermediate result avoids retyping and the mistakes that come with it.
- •It is most useful for problems with three or more steps.
- •Clear memory before starting a new problem.
What makes this scientific calculator useful
Visible DEG/RAD indicator
The current angle mode is always shown, so you can check it before a trig calculation.
Labelled memory keys
M+, MR and MC are plain buttons, which keeps multi-step working in one flow.
Keyboard support
Type numbers and operators on your keyboard, press Enter for equals and Escape to clear.
Constants
Use π, e and φ as exact values instead of typing rounded numbers.
Professional applications
Engineering
Engineers use trig for angles, forces and components, and need the right angle mode to get usable results.
A 30° slope with a 10 m run rises about 5.77 m, using tan(30°) × 10 in degree mode.
Physics
Physics problems use natural logs for decay and trig for waves and projectile motion.
A half-life problem uses ln(2) ≈ 0.693 to find the decay constant.
Chemistry
Chemists use base-10 logs for pH and for concentration scales.
pH = −log[H⁺], so a hydrogen ion concentration of 1 × 10⁻⁷ mol/L gives pH 7.
Historical context
Frequently asked questions
What is the difference between DEG and RAD?+
DEG measures angles in degrees, with 360 in a full circle. RAD measures angles in radians, with 2π in a full circle. sin(30°) in DEG mode gives the same answer as sin(π/6) in RAD mode. If your answer is off by about 57.3, check the mode.
What is the difference between log and ln?+
log is the base-10 logarithm and ln is the natural logarithm with base e (about 2.718). log(100) = 2 and ln(100) ≈ 4.605. Use log for pH and decibels, and ln for growth, decay and calculus.
How do I use the memory keys?+
M+ adds the displayed value to memory, MR recalls it and MC clears it. Store an intermediate result, carry on with the next step, then recall it when you need it.
Can I use this calculator in an exam?+
Usually not. Most exams require an approved physical calculator, and browser tools are normally not allowed in the exam room. Use this one for homework, revision and checking your working, and read your exam board’s rules.
How is a scientific calculator different from a basic one?+
A basic calculator handles add, subtract, multiply and divide. A scientific calculator also has trigonometry, logarithms, powers, roots, constants and memory, which are used in physics, chemistry, engineering and higher maths.
What this calculator cannot do+
It does not do symbolic algebra, matrices or calculus, and it cannot graph functions or run programs. For those you need a graphing calculator or maths software.