展开 u(t-(7pi)/2)*sin(t)

解答

展开

u (t - \frac{7 π}{2}) \cdot sin (t)

u t sin (t) - \frac{7 π u sin ( t )}{2}

求解步骤

u (t - \frac{7 π}{2}) sin (t)

= u sin (t) (t - \frac{7 π}{2})

使用分配律:

a (b - c) = ab - a c

a = u sin (t), b = t, c = \frac{7 π}{2}

= u sin (t) t - u sin (t) \frac{7 π}{2}

= u t sin (t) - \frac{7 π}{2} u sin (t)

化简

u t sin (t) - \frac{7 π}{2} u sin (t) : u t sin (t) - \frac{7 π u sin ( t )}{2}

= u t sin (t) - \frac{7 π u sin ( t )}{2}

e x p an d y^{''} (x) - (1 + x) y

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e x p an d (2 x - y) d x