计算a-x分之1减a+x分之1减a^2+x^2分之2x减a^4+x^4分之4x^3加x

=1/(a-x)-1/(a+x) -2x/(a²+x²)-4x³/(a^4+x^4)-8x^7/(a^8+x^8)
=[(a+x)-(a-x)]/ (a²-x²)-2x/(a²+x²)-4x³/(a^4+x^4)-8x^7/(a^8+x^8) 前两项通分合并同类项
=2x/(a²-x²)-2x/(a²+x²) -4x³/(a^4+x^4)-8x^7/(a^8+x^8)
=4x³/(a^4-x^4)-4x³/(a^4+x^4)-8x^7/(a^8+x^8)
=8x^7(a^8-x^8)-8x^7/(a^8+x^8)
=16x^15/(a^16-x^16)