展开 (a+b)cos(a)-cos(a+b)sin(a)

解答

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(a + b) cos (a) - cos (a + b) sin (a)

a cos (a) + b cos (a) - cos (a + b) sin (a)

求解步骤

(a + b) cos (a) - cos (a + b) sin (a)

= cos (a) (a + b) - cos (a + b) sin (a)

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cos (a) (a + b) : a cos (a) + b cos (a)

= a cos (a) + b cos (a) - cos (a + b) sin (a)

e x p an d \frac{x ^{2} + 5 x + 6}{( x - 1 ) ( x ^{2} + 2 x + 3 )}

e x p an d (- 5, - 8) y (- 5, - 6)

e x p an d (\frac{1}{x} = \frac{5}{4} - \frac{3}{y + 1}) 4

s im pl i f y (x + 5) (x - 5) (x + 1 - i) (x - 1 - i)

e x p an d \frac{2 ( x + 6 )}{x - 2}