展开 (t-3)cos(t-3)

解答

展开

(t - 3) cos (t - 3)

t cos (t - 3) - 3 cos (t - 3)

求解步骤

(t - 3) cos (t - 3)

= cos (t - 3) (t - 3)

使用分配律:

a (b - c) = ab - a c

cos (t - 3) (t - 3) = cos (t - 3) t - cos (t - 3) \cdot 3

= cos (t - 3) t - cos (t - 3) \cdot 3

= t cos (t - 3) - 3 cos (t - 3)

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