Introduction to Trigonometry Question - CBSE

Question

If $\sec 4A = \csc(A - 20^\circ)$, where $4A$ is an acute angle, find the value of $A$. (Note: Standard angle relationship $\sec X = \csc Y \Rightarrow X + Y = 90^\circ$).

Accepted Answer

$4A + A - 20^\circ = 90^\circ \Rightarrow 5A = 110^\circ$. [1.0 Mark]
$A = 22^\circ$. [1.0 Mark]

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🎯 Official CBSE Marking Scheme:
Setting $4A + A - 20^\circ = 90^\circ$: 1.0 Mark
Solving $A = 22^\circ$: 1.0 Mark

Question:

Step-by-Step Solution

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