If sin (A + B) = 1 and cos (A − B) = 1, then find the value of cot 2A, where 0° ≤ (A + B) ≤ 90° and A ≥ B
WBBSE
Class X
Mathematics
Trigonometric Ratios And Trigonometric Identities
02 Mark
2024
Given: sin (A + B) = 1
⇒ A + B = 90° —— (i)
Also, cos (A − B) = 1
⇒ A − B = 0°
⇒ A = B.
Now, A + B = 90° and A = B
⇒ 2A = 90°
⇒ A = 45°.
So, cot 2A = cot 90° = 0
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