f(x)=sra,f()=∫ sint dt=0. 2 SIn 2sin x f(x)=2·2x= hy(x)k=(-1 2Jox'f'(x)dr 2xsinx dx 2 sinx dx 2 JO aLcos x o=(cos 1-1). 2 上页 = 2 1 , sin ( ) x dt t t  f x , 2sin 2 sin ( ) 2 2 2 x x x x x f  x =  =  1 0 xf (x)dx (1) 2 1 = f  −  1 0 2 ( ) 2 1 x f x dx  = − 1 0 2 2 sin 2 1 x x dx  = − 1 0 2 2 sin 2 1 x dx   1 0 2 cos 2 1 = x (cos1 1). 2 1 = − 0, sin (1) 1 1 = dt = t t f