# Version v5.3.1
mchipm1*0.0033950534040495324 + (mchi1*mchi1*(-0.753678714667031)/(mchipm1*(mchi1 + (mchi1 + (mchi1 + mchipm1 + mchipm1 - 1*(-1.3238102377649212))*0.0005938908358292764/(-(mchi1 - mchipm1) - 0.15810562309423207*(-(mchi1 - mchipm1) - 0.15810562309423207)))/(-0.48181628950593397))) - 1.289952325711101)**3 - 1.3238102377649212 + (mchi1 - 1*0.8979487806648314)/mchipm1