展开 e^{3t}(t+cos(t))^2

解答

展开

e^{3 t} (t + cos (t))^{2}

e^{3 t} t^{2} + 2 e^{3 t} t cos (t) + e^{3 t} cos^{2} (t)

求解步骤

e^{3 t} (t + cos (t))^{2}

(t + cos (t))^{2} = t^{2} + 2 t cos (t) + cos^{2} (t)

= e^{3 t} (t^{2} + 2 t cos (t) + cos^{2} (t))

打开括号

= e^{3 t} t^{2} + e^{3 t} \cdot 2 t cos (t) + e^{3 t} cos^{2} (t)

= e^{3 t} t^{2} + 2 e^{3 t} t cos (t) + e^{3 t} cos^{2} (t)

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

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

s im pl i f y (4 x + 3 y) (x - 3 y)

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e x p an d \frac{sin ( a ) - cot ( a ) ( 1 - cos ( a ) )}{1 - cos ( a )}