1、cosx=1/2x=2kπ±π/3k=0, 1,2....10个解，从k=0起 -π/3, π/3, 5π/3, 7π/3, 11π/3, 13π/3, 17π/3, 19π/3, 23π/3, 25π/3不小于0的最小值为π/32、arcsinx大于arcsin(2x+1)即x>2x+1x<-1/23、设过(3,1)的直线为y-1=k(x-3) y=kx+1-3k代入x^2-y^2=1
得(1-k^2)x^2-2k(1-3k)x-(9k^2-6k+2)=0只要4k^2(1-3k)^2+4(1-k^2)(9k^2-6k+2)=0化简得4k^2-3k+1=0因△=(-3)^2-4*4*1= |
