A.cscx tgx B.secx ctgx C.-cscx ctgx D.1/cosx
A.7cos(7x+3) B.7sinx C.7cosx D.7sin(7x+3)
A.初等函數(shù)的導(dǎo)函數(shù)是初等函數(shù) B.連續(xù)函數(shù)一定存在原函數(shù) C.初等函數(shù)的原函數(shù)是初等函數(shù) D.非初等函數(shù)沒有原函數(shù)