(sint+cost)/(cost-sint)怎么算的,等于tan(t+π/4)

∫cost/(sint+cost)dt ∫sint/(cost+sint)dt sint/(1-cost)求导 (cost-sint)/(sint-cost) 的结果不知道等不等于 -(sint-cost)/(sint-cost)也就是-1 ∫dt/(1+sint+cost) (sint cost)^2 的不定积分 sint/1-cost=什么 证明：f(x)=x*cos(x)不是周期函数证明：假设y=xcosx是周期函数,因为周期函数有f(x+T)=f(x)xcosx=（x+T)cos(x+T)=xcosx*cosT-xsinx*sinT+Tcosx*cosT-Tsinx*sinT所以cosT=1 T=kπ/2-xsinx*sinT+Tcosx*cosT-Tsinx*sinT=0-xsinx*sinT-Tsinx*si sint/(1-cost)=cost/2怎么推? 如何直接看出0到pai/2定积分cost/(sint+cost)与sint/(sint+cost)相等? cost的平方/sint 的不定积分 (1/(1+sint+cost))dt不定积分 为什么∫(2sint+cost)+2(2cost-sint)/2sint+cost dt = (t+2ln|2sint+cost|)+C? 求fxo(sint+cost·sint)dt的最大值求fxo(sint+cost·sint)dt的 最大值 t趋于0时为什么lim(sint+cost-1)/t=lim(cost-sint)=1) x=sint-cost y=sint+cost 求它得普通方程 (sint+cost)/(cost-sint)怎么算的,等于tan(t+π/4) 求x=e^t*cost,y=e^t*sint所确定的函数的二阶导数,求讲解x't=(e^t)(sint+cost)y't=(e^t)(cost-sint)x''t=(e^t)(sint+cost+cost-sint)=2(e^t)costy''t=(e^t)(cost-sint-sint+cost)=-(e^t)sintdy/dx=(cost-sint)/(sint+cost)d^2 y/d(x^2)=d(dy/dx)/dx=(y''x