Question
The value of cos² 10° + cos² 20° + cos² 30° +
……. + cos² 90° isSolution
ATQ, We know cos(90° - A) = sin A cos² 10 + cos² 20 + cos² 30° +……. + cos² 90° = cos² 1 + cos² 20 + cos² 30° + cos² 40° + sin² 40+ sin² 30° + sin² 20 + sin² 10+ cos² 90 = (sın² 10° + cos2 10) + (sin² 20 + cos² 20) + (sin² 30° + cos² 30) + (sin² 40+ cos² 40°) + cos² 90 = 1+1+1+1+0 = 4
More Quant Miscellaneous Questions
√3598 × √(230 ) ÷ √102= ?
15% of 2400 + (√ 484 – √ 256) = ?
(13)2 - 3127 ÷ 59 = ? x 4
6269 + 0.25 × 444 + 0.8 × 200 = ? × 15
...(53 + 480 ÷ 4)% of 20 = ?% of 70
Find the simplified value of the following expression:
62 + 122 × 5 - {272 + 162 - 422}
(15 × 225) ÷ (45 × 5) + 480 = ? + 25% of 1240
√ [? x 11 + (√ 1296)] = 16
11 × 25 + 12 × 15 + 14 × 20 + 15 = ?
