The greatest among (sin1+cos1),(sin1+cos1),(sin1−cos1) and 1 is
sin1+cos1
sin1−cos1
1
sin1>sin1>sin21,cos1>cos1>cos21
Adding (sin1+cos1)>(sin1+cos1)>(sin21+cos21)
⇒(sin1+cos1)>(sin1+cos1)>1