展开 (sin(2x)sin(x)+cos(4x)cos(x))sec(2x)

解答

展开

(sin (2 x) sin (x) + cos (4 x) cos (x)) sec (2 x)

cos (4 x) cos (x) sec (2 x) + tan (2 x) sin (x)

求解步骤

(sin (2 x) sin (x) + cos (4 x) cos (x)) sec (2 x)

= sec (2 x) (sin (2 x) sin (x) + cos (4 x) cos (x))

使用分配律:

a (b + c) = ab + a c

sec (2 x) (sin (2 x) sin (x) + cos (4 x) cos (x)) = sec (2 x) sin (2 x) sin (x) + sec (2 x) cos (4 x) cos (x)

= sec (2 x) sin (2 x) sin (x) + sec (2 x) cos (4 x) cos (x)

化简

sec (2 x) sin (2 x) sin (x) + sec (2 x) cos (4 x) cos (x) : cos (4 x) cos (x) sec (2 x) + tan (2 x) sin (x)

= cos (4 x) cos (x) sec (2 x) + tan (2 x) sin (x)

e x p an d - \frac{7}{( s ^{2} - 6 s + 8 ) ( s - 3 )}

s im pl i f y 11 (17 + 122)

e x p an d \frac{5 x + 13}{( x - 1 ) ( x + 5 )}

e x p an d \frac{1 - e ^{- 3 s}}{s ( s ^{2} + 2 s + 10 )}

e x p an d (1 + 2 cos (t)) \cdot (2 sin (t))