Practicing Success
The value of $cot^2 46° - sec^2 44° + (sin^2 1° + sin^2 3° + sin^2 5° + ... + sin^2 89°)$ is : |
23.5 20.5 22.5 21.5 |
21.5 |
$cot^2 46° - sec^2 44° + (sin^2 1° + sin^2 3° + sin^2 5° + ... + sin^2 89°)$ Using :- If sinA = cosB then A + B = 90° And sin²A + sin²B = 1 Iff A + B = 90° tan²44° - sec²44° + ( sin²1° + sin²3° + sin²5° + ......+ sin²89° ) From 1° tp 89° there are 88 angles excluding 45° . so, Number of pairs = 22 { we know, sec²44° - tan²44° = 1 } = -1 + 22 + sin30° = 21 + \(\frac{1}{2}\) = 21.5 |