Math, asked by rama1402, 11 months ago

using the formula cos A = root 1+ cos2A / 2 find the value of cos 15​

Answers

Answered by azizalasha
9

Answer:

(√3 + 1) ÷ 4

Step-by-step explanation:

cos A = root 1+ cos2A / 2

cos A =√ (1+ cos2A) / 2

cos 15° =√ (1+ cos 30°) / 2

cos 15° =√ (1+ √3/2) / 2  =√ (1+ 2√3/4) / 2  √ (4+ 2√3/√4 * 2

cos 15° = (√3 + 1) ÷ 4

Answered by aggarwalhitesh810
0

Answer:

(√3 + 1) ÷ 4

Step-by-step explanation:

cos A = root 1+ cos2A / 2

cos A =√ (1+ cos2A) / 2

cos 15° =√ (1+ cos 30°) / 2

cos 15° =√ (1+ √3/2) / 2  =√ (1+ 2√3/4) / 2  √ (4+ 2√3/√4 * 2

cos 15° = (√3 + 1) ÷ 4

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