// Numbas version: exam_results_page_options {"name": "Sheet 2 Q8 Chain Rule with custom feedback", "extensions": [], "custom_part_types": [], "resources": [], "navigation": {"allowregen": true, "showfrontpage": false, "preventleave": false, "typeendtoleave": false}, "question_groups": [{"pickingStrategy": "all-ordered", "questions": [{"name": "Sheet 2 Q8 Chain Rule with custom feedback", "tags": [], "metadata": {"description": "Chain rule question with feedback given for anticipated student errors.", "licence": "Creative Commons Attribution-NonCommercial 4.0 International"}, "statement": "

Find the slope of the tangent to the curve $f(t)=\\ln (\\cos t)$ when $\\displaystyle t=\\frac{\\pi}{4}$.

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First, find the derivative:

\n

$f'(t) = $ [[0]]

\n

\n

Next, find the slope of the tangent when $\\displaystyle t = \\frac{\\pi}{4}$:

\n

Slope = [[1]]

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