题目

设函数f(x)=a·b,其中向量a=(2cosx,1),b=(cosx,sin2x),x∈R.(1)若f(x)=1-且x∈［-,］,求x;(2)若函数y=2sin2x的图象按向量c=(m,n)(|m|＜)平移后得到函数y=f(x)的图象,求实数m、n的值. 答案：剖析:(1)欲求x,需把f(x)化成一个角的一个三角函数形式,然后解三角方程.(2)欲求m、n,只需知道怎样由y=2sin2x的图象得到y=f(x)的图象.解:(1)依题设,f(x)=2cos2x+sin2x=1+2sin(2x+).    由1+2sin(2x+)=1-,得sin(2x+)=-.∵-≤x≤,∴-≤2x+≤.∴2x+=-,即x=-.    (2)函数y=2sin2x的图象按向量c=(m,n)平移后得到函数y=2sin2(x-m)+n的图象,即函数y完形填空 　　Radio and television 1 very popular 2 the world today. 3 of the people watch TV, perhaps more people 4 the radio. 　　The TV is of course 5 than the radio. 6  TV you can see and hear what is 7 in the world. However, radio is 8 disappearing. It is still 9 us. And 10 of listeners is becoming 11 . A transistor radio is 12 very small. Ii is very 13 to carry. You can listen to it 14 the bus or on your bike when you 15 to work. 16 , radio broadcasts are 17 for blind people. The sight of many old people is not 18 enough to watch TV. Then when people are working, they can't watch TV but they can listen to music or news 19 the radio. What's more, radio is much 20 than TV. 1． [　　] A．were B．was C．are D．has been 2． [　　] A．in B．on C．to D．of 3． [　　] A．The million B．Million C．A million D．Millions 4． [　　] A．hear B．listen to C．heard D．listened to 5． [　　] 　　A．useful 　　B．more usefully 　　C．more useful 　　D．much useful 6． [　　] A．In B．To C．For D．On 7． [　　] A．happening B．happen C．happened D．happened to 8． [　　] A．nor B．neither C．still D．not 9． [　　] A．and B．with C．having D．living 10． [　　] A．number B．the numbers C．a number D．the number 11． [　　] A．more B．large C．less D．huger 12． [　　] A．sometimes B．some time C．sometime D．some times 13． [　　] A．easily B．difficult C．easy D．heavy 14． [　　] A．by B．on C．with D．to 15． [　　] A．going B．go C．come D．coming 16． [　　] A．Except B．Except for C．Besides D．Besides that 17． [　　] A．harmful B．convenient C．priceless D．money 18． [　　] A．good B．better C．well D．best 19． [　　] A．by B．of C．over D．in 20． [　　] A．useful B．important C．cheap D．cheaper