Trignometry

Quantitative Aptitude (RRB NTPC)

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

If x, y are acute angles, 0 < x + y < 90° and sin (2x – 20°) = cos (2y + 20°), then the value of tan (x + y) is :

1/√3

√3

Explanation:

sin (2x – 20°) = cos (2y + 20°)
⇒ sin (2x – 20°) = cos (90° – 2y – 20°)
⇒ sin (2x – 20°) = sin (70° – 2y)
⇒ (2x – 20°) = (70° – 2y)
⇒ 2x + 2y = 70° + 20° = 90°
⇒ x + y = 45°
taking tan both side, we get
∴ tan (x + y) = tan 45° = 1

By: Amit Kumar

Profile ResourcesReport error

Trial Period Ended