Trignometry

Quantitative Aptitude (CHSL)

Title

45:30

Video Progress

8 of 24 completed

Notes Progress

5 of 15 completed

MCQs Progress

38 of 100 completed

Subjective Progress

8 of 20 completed

Continue to Next Topic

Indian Economy - Understanding the basics of Indian economic system

Next Topic

Download Solution PDF

sin² 5° + sin² 10° + sin² 15° + ... + sin² 85° + sin² 90° is equal to

7 1/2

8 1/2

9 1/2

Explanation:

sin² 5° + sin² 10° + sin² 15° + ..... + sin² 85° + sin² 90°
= (sin² 5° + sin² 85°) + (sin² 10° + sin² 80°) + ..... to 8 terms + sin² 45° + sin² 90°
= (sin² 5° + cos² 5°) + (sin² 10° + cos² 10°) + .... to 8 terms + sin² 45° + sin² 90°
[? sin (90° – Θ) = cos Θ]
= 1 + 1 + ... to 8 terms + (1/√2)²+ (1)²
= 8 + 1/2 + 1
= 9 1/2

By: Amit Kumar

Profile ResourcesReport error

Trial Period Ended