求不定积分√(X^2-9)/X
问题描述：
求不定积分√(X^2-9)/X
答
∫√(x^2-9)dx/x
x=3secu
=∫3tanud(3secu)/(3secu)
=3∫sinudsecu
=3sinusecu-3∫secudsinu
=3tanu-3∫du
=3tanu-3u+C
=3√(x^2-9) -3arccos(3/x)+C