希腊字母等特殊字符用\加拼音如α\alphaβ\betaγ\gammaθ\thetaΘ\ThetaГ\Gammaδ\deltaΔ\Deltaξ\xiΞ\Xiη\eltaε\epsilongζ\zetaμ\miuυ\nuτ\tauλ\lamda∧\Lamdaπ\pi∏\Piσ\sigma∑\Sigmaφ\phiΦ\Phiψ\psiΨ\Psiχ\chiω\ommigaΩ\Ommiga\leq\geq不等于\neq\ll\gg正负\pm左箭头\leftarrow右箭头\rightarrow上箭头\uparrow