lesson
Handle failure without hiding it
1 · Learn
An application should distinguish expected validation failures from unexpected faults. A useful message helps the user correct input, while technical diagnostics should avoid revealing secrets. Silently pretending a failed save succeeded corrupts trust.
Do not catch every error and return a success message. Preserve the unsaved input where appropriate and make the actual outcome clear.
2 · Worked example
If storage is unavailable, 'Saved successfully' is false even if the form looks normal. A clear retry message should not expose a connection password.
3 · Your turn
What is wrong with reporting success after a database write failed?
Check your answer
It misrepresents the state and may cause the user to believe unsaved work is safe.
4 · Apply your learning
Design separate messages for invalid input and failed storage using fictional data.
Adult guidance and safety
Work in an approved local sandbox with invented records and test accounts. Do not access other people's systems or collect real credentials. Practical project evidence is required in addition to these explanations; this is not a specified GCSE Computer Science course.
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Typed notes are not submitted answers.
Check a calculation · Year 5 onward
Use this only when your teacher or adult allows a calculator for the task. Show your thinking first. It does not replace mental or written arithmetic and does not mark your lesson answer.
Powers, roots and trigonometry · Year 7 onward
Use only when the task allows a calculator. Choose one operation at a time and record your working. Trigonometry here always uses degrees (DEG), not radians. Inverse sine, cosine and tangent return an angle, not a reciprocal. Keep exact fractions and π in answers when requested.
Approximate numerical results use up to 12 significant digits. Inverse sine returns −90° to 90°, inverse cosine 0° to 180°, and inverse tangent −90° to 90°; these are principal values, not every possible solution of a trigonometric equation.
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