已知
=(−sint,cost),=(1,−t),⊥,则(1+t
2)(1+cos2t)-2的值为______.
人气:431 ℃ 时间:2020-03-22 23:27:03
解答
因为a=(−sint,cost),b=(1,−t),由a⊥b,得:-sint×1+(-t)×cost=0,所以sint+tcost=0,cos2t=sin2tt2,(1+t2)(1+cos2t)-2=2(1+t2)cos2t-2=2(1+t2)sin2tt2−2=2sin2tt2+2sin2t−2.故答案为2sin2tt...
推荐
- 已知a向量=(-sint,cost),向量b=(1,-t),向量a垂直向量b,则(1+t^2)*(1+cos2t)-2的值为
- 曲线x=cost,y=sint,z=sint+cost在对应t=0的点处的切向量是多少
- 已知向量m=(a-sint,-1/2),n=(1/2,cost)
- t属于(0,π),sint+cost=1/3,求cos2t
- 设两个向量a=(n+2,n^2-(cost)^2)b=(m,m/2+sint),其中n m t为实数,若a=2b,则n/m的取值范围是?
- To suggest that the student did not do the reading
- -lg5 -lg7 怎么化成1\5 1\7
- at ease,be likely to,in general,lose face,defend aganist,turn one's back to用五句话编一个故事
猜你喜欢