- 问题详情:用数学归纳法*:tanα·tan2α+tan2α·tan3α+…+tan(n-1)α·tannα=-n(n∈N*,n≥2).【回答】*(1)当n=2时,右边=-2=-2==tanα·tan2α=左边,等式成立.(2)假设当n=k(k∈N*且k≥2)时,等式成立,即tanα·tan2α+tan2α·tan3α+…+tan(k-1)α·tankα=-k,那么当n=k+1时,tanα·tan2α+tan2α·tan3α+...
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- KearnsgothispatentrightsbackfromTann.TheyagreedthatKearnswouldassignhisrightstotheintermittentwipertoTann,andTannwouldtakeoverthecostofgettingthepatents.Kearnsfinallytookaction:“Iwaitedforarainyday,thenIdroveovertoseeDaveTann.”Wespentthenightinthev...
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