展开 (y-3)^2cos(t)

解答

展开

(y - 3)^{2} cos (t)

y^{2} cos (t) - 6 y cos (t) + 9 cos (t)

求解步骤

(y - 3)^{2} cos (t)

= cos (t) (y - 3)^{2}

展开

(y - 3)^{2} : y^{2} - 6 y + 9

= cos (t) (y^{2} - 6 y + 9)

使用分配律:

m (a + b + c) = ma + mb + m c

cos (t) (y^{2} - 6 y + 9) = cos (t) y^{2} + cos (t) (- 6 y) + cos (t) \cdot 9

= cos (t) y^{2} + cos (t) (- 6 y) + cos (t) \cdot 9

化简

cos (t) y^{2} + cos (t) (- 6 y) + cos (t) \cdot 9 : y^{2} cos (t) - 6 y cos (t) + 9 cos (t)

= y^{2} cos (t) - 6 y cos (t) + 9 cos (t)

e x p an d \frac{( x ^{2} + 1 ) ( x ^{4} - x ^{2} + 1 )}{2 x ^{3}}

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

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

s im pl i f y (\frac{5}{x + 2} + \frac{12}{x ^{2} - 4} + \frac{3}{2 - x}) (x + 2)

e x p an d \frac{x + 1}{x ( x - 2 )}