Find  the value of sin25+sin210+sin215............sin290

Asked by apporv1999 | 19th Aug, 2014, 03:20: PM

Expert Answer:

S i n squared space 5 plus S i n squared 10 plus.... plus sin squared 90 W e space c a n space r e w r i t e space space S i n squared 5 equals C o s squared 85 S i m i l a r l y space S i n squared 10 equals C o s squared 80....... sin squared 40 equals C o s squared 50  H e n c e space w e space g e t open parentheses C o s squared 85 plus S i n squared 85 close parentheses plus open parentheses C o s squared 80 plus S i n squared 80 close parentheses plus........ plus open parentheses C o s squared 50 plus S i n squared 50 close parentheses plus S i n squared 45 plus S i n squared 90 equals 1 plus 1 plus 1 plus 1 plus 1 plus 1 plus 1 plus 1 plus 1 half plus 1 equals 9 1 half equals 19 over 2

Answered by Dharma Teja | 19th Aug, 2014, 03:41: PM