CameraIcon
CameraIcon
SearchIcon
MyQuestionIcon
MyQuestionIcon
1
You visited us 1 times! Enjoying our articles? Unlock Full Access!
Question

sin25+sin210+sin215+...+sin285+sin290=


A
934
No worries! We‘ve got your back. Try BYJU‘S free classes today!
B
8
No worries! We‘ve got your back. Try BYJU‘S free classes today!
C
9
No worries! We‘ve got your back. Try BYJU‘S free classes today!
D
912
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
Open in App
Solution

The correct option is D 912

Given expression is:

sin25+sin210+sin215+...+sin285+sin290

We know that sin90=1 or sin290=1

Similarly, sin45=12 or sin245=12 and the angles are in A.P. of 18 terms. We also know that

sin285=[sin(905)]2=cos25.

Therefore from the complementary rule, we find sin25+sin285=sin25+cos25 = 1.

Therefore,

sin25+sin210+sin215+...+sin285+sin290

=(1+1+1+1+1+1+1+1)+12+1=912


flag
Suggest Corrections
thumbs-up
3
Join BYJU'S Learning Program
similar_icon
Related Videos
thumbnail
lock
Trigonometric Ratios of Allied Angles
MATHEMATICS
Watch in App
Join BYJU'S Learning Program
CrossIcon