Question

cos20×cos100+cos100×cos140-cos140×cos200

Answer 1

here friend's your may be this:
not sure but follow:
(20+100)+cos100*140-cos140*cos200
=(120*100)*(140/140)*cos 200.
=12000*1*cos200.
=12000+200.
=12200.Ans//
hope it helps you a lot