(1)
cos x dx
coe 2X-1
2
dx
17
Coe 2x=cosx-(1-cos²x)
2 coax = coa 2X-1
1 (sin 2x-1/2-x)
2
= = = 2x = x + C
4
2
(2)
cor 5X cos 2x dr
cos (α+B) = cord corß - sind siß
CAR (α-B) = cos & cosß + sind siß
2 cozα cosß = cos (αTB) + cos (α-B)
= 5 + { con (5x+2x) + coa (5x-2x) by dx
= 1 ( — sin 7 x + sin 3x) +6
=
IN
14
sin 7X + + sin 3x + C
積和