English

Find θ if 0° < θ ≤ 90°. cos θ = cos 60° cos 30° + sin 60° sin 30° - Mathematics

Advertisements
Advertisements

Question

Find θ if 0° < θ ≤ 90°.

cos θ = cos 60° cos 30° + sin 60° sin 30°

Sum
Advertisements

Solution

Given:

0° < θ ≤ 90°

cos θ = cos 60° cos 30° + sin 60° sin 30°

Step 1: 

cos θ = `1/2 ⋅ sqrt3/2 + sqrt3/2 ⋅ 1/2`

= `sqrt3/4 + sqrt3/4`

= `sqrt3/2 → θ = 30°`

shaalaa.com
  Is there an error in this question or solution?
Chapter 19: Trigonometry - EXERCISE 19C [Page 237]

APPEARS IN

B Nirmala Shastry Mathematics [English] Class 9 ICSE
Chapter 19 Trigonometry
EXERCISE 19C | Q II. 6. | Page 237
Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×