cos75⁰ এর মান হয় -

Explanation:

Another Explanation (5): cos75° এর মান নির্ণয়: আমরা জানি, cos(A + B) = cosA cosB - sinA sinB cos75° = cos(45° + 30°) = cos45° cos30° - sin45° sin30° আমরা জানি, cos45° = \( \frac{1}{\sqrt{2}} \) , cos30° = \( \frac{\sqrt{3}}{2} \) , sin45° = \( \frac{1}{\sqrt{2}} \) , sin30° = \( \frac{1}{2} \) সুতরাং, cos75° = \( \frac{1}{\sqrt{2}} \cdot \frac{\sqrt{3}}{2} - \frac{1}{\sqrt{2}} \cdot \frac{1}{2} \) = \( \frac{\sqrt{3}}{2\sqrt{2}} - \frac{1}{2\sqrt{2}} \) = \( \frac{\sqrt{3} - 1}{2\sqrt{2}} \) অতএব, cos75° = \( \frac{\sqrt{3} - 1}{2\sqrt{2}} \) 🥳🥳🥳