【已知f(x)=(x-1)(x-2)(x-3)(x-4)(x-5),则f′(1)=______.】
<p>问题:【已知f(x)=(x-1)(x-2)(x-3)(x-4)(x-5),则f′(1)=______.】<p>答案:↓↓↓<p class="nav-title mt10" style="border-top:1px solid #ccc;padding-top: 10px;">牛建丽的回答:<div class="content-b">网友采纳 ∵f(x)=(x-1)(x-2)(x-3)(x-4)(x-5), ∴令g(x)=(x-2)(x-3)(x-4)(x-5), 则f(x)=(x-1)g(x) ∴f′(x)=(x-1)′g(x)+(x-1)g′(x)=g(x)+(x-1)g′(x), 则f′(1)=g(1)+(1-1)g′(1)=g(1), ∵g(1)=(1-2)(1-3)(1-4)(1-5)=24, ∴f′(1)=g(1)=24, 故答案为:24.
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