3^n在Word里則輸入3n,選中n,把n作為上標（可按Ctrl+Shift+ =鍵),或用公式編輯器或用Mathtpye
補充一下Mathtpye的下載地址是 ://jscz.driversky.com/down/ha_mathtype52a_zbf.exe
3^n
3n
