 ×     #### Thank you for registering.

One of our academic counsellors will contact you within 1 working day.

Click to Chat

1800-1023-196

+91-120-4616500

CART 0

• 0

MY CART (5)

Use Coupon: CART20 and get 20% off on all online Study Material

ITEM
DETAILS
MRP
DISCOUNT
FINAL PRICE
Total Price: Rs.

There are no items in this cart.
Continue Shopping
```

```
7 months ago

```							Dear student As cos 179 = cos (180-1) = - cos1SimilarlyCos 178 = - cos2Cos 177 = - cos3 Hencw when adding all terms cancelled out.Only cos90 + cos180 is remaining Now cos 90 = 0 and cos 180 = - 1 Hence final answer is  -1.
```
7 months ago
```							Dear student The given expression can be rearranged as:(Cos 1 + cos 179) + (cos2 + cos 178) + (cos3+ cos177) +…. + (cos89 + cos 91) + (cos90) + cos180But we know that: cos(180 - x)= - cos x, where x is angle in degree. So all the bracket totals except last 2 terms will be zero.So given expression is: 0 + (cos90) + ( cos180)= 0 + 0 + (-1)=-1.Answer: -1.
```
7 months ago
Think You Can Provide A Better Answer ?

## Other Related Questions on Trigonometry

View all Questions »  ### Course Features

• 731 Video Lectures
• Revision Notes
• Previous Year Papers
• Mind Map
• Study Planner
• NCERT Solutions
• Discussion Forum
• Test paper with Video Solution  ### Course Features

• 31 Video Lectures
• Revision Notes
• Test paper with Video Solution
• Mind Map
• Study Planner
• NCERT Solutions
• Discussion Forum
• Previous Year Exam Questions