#### 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

# If the line joining circumcentr and incentre is parallel to BC then cosB+cosC=

26 Points
5 years ago
SO ANSWER IS I.E COSB+COSC=1 HERE this angle theta is the angle between IO and LO it is zero in this case so our answer is one.
26 Points
5 years ago
I had seen that above image submitted by me is unclear . so to view the solution please click the below link . I don’t see ny option to attach image. copy it and see in broswer. askiitans1.weebly.com/link-1.html
26 Points
4 years ago

I had seen that above image submitted by me is unclear . so to view the solution please click the below link . I don’t see ny option to attach image. copy it and see in broswer. askiitans1.weebly.com/link-1.html
mycroft holmes
272 Points
4 years ago
Drop perpendiculars from I and O on to BC and let the feet of the perpendiculars be P and Q resp.

Also OQ = R cos A.

Since OI is parallel to BC, we have IP = OQ i.e. r = R cos A and hence

$1+\frac{r}{R} = 1+\cos A$

We know that $1+\frac{r}{R} = \cos A + \cos B + \cos C$

Thus we obtain $1+\cos A = \cos A + \cos B + \cos C \Rightarrow \boxed {\cos B+\cos C =1}$