AP EAMCET · Maths · Trigonometric Ratios & Identities
What is the value of
- A
- B
- C
- D
Answer & Solution
Correct Answer
(B)
Step-by-step Solution
Detailed explanation
Let cos A=cos2212∘ ⇒A=2212∘ Using formula, cos 2A=2cos2A-1 ⇒cos 45∘=2cos2A-1 ⇒12+1=2cos2A ⇒2cos2A=1+22 ⇒cosA=1+222 Hence, cos A=cos2212∘=1+222
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