Hi,
Math.pow() should do the job 
V7 Variables List for more.
edit: You’re formula have 2 grammatical problems.
The “$” at the start shouldn’t be there
The “/ month” should be inside [[ ]] brackets. In fact everything outside bracket will be interpreted as pure string.
ie. [[ 4 + 2 ]] + 3 will output the string : " 6 + 3 "
At the end it should look like :
[[Math.pow( YourFormula , Term ) / Month]]