Expand and evaluate sigma notation
Evaluate \(\sum_{k=5}^{9}(4k - 5)\). State the first term, the last term, the number of terms, and the final sum.
Worked practice: sigma notation
Expand the first and last terms, count the terms, then add the series.
Write a full answer
Now write the response in full, in your own words — this is what the exam asks for. The AI marks it on the same moves you built above (focus, evidence, technique, judgement) and gives feedback on reasoning, evidence, and expression.