∫sinx√(1+cosx^2)dx
=-∫√(1+cosx^2)dcosx
用y=cosx ,有
=-∫√(1+y^2)dy
=-y/2*√(1+y^2)-1/2*ln(y+√(1+y^2))+c
又y=cosx,代回得;
=-cosx/2*√(1+cosx^2)-1/2*ln(cosx+√(1+cosx^2))+c
∫sinx√(1+cosx^2)dx
=-∫√(1+cosx^2)dcosx
用y=cosx ,有
=-∫√(1+y^2)dy
=-y/2*√(1+y^2)-1/2*ln(y+√(1+y^2))+c
又y=cosx,代回得;
=-cosx/2*√(1+cosx^2)-1/2*ln(cosx+√(1+cosx^2))+c