Keyboard Access:x y x=yHP-28: the = key HP48: LS-0 HP49/50: RS-[+/–] ALPHA-RS-[+/–]Equals analytic function: Returns an equation formed from the two arguments.
The equals sign equates two expressions such that the difference between them is zero.
In Symbolic Results mode, the result is an algebraic equation. In Numerical Results mode, the result is the difference of the two arguments because acts equivalent to (subtraction). This allows expressions and equations to be used interchangeably as arguments for symbolic and numerical rootfinders.
Caution! is NOT a “test” function! It is mathematically the same as subtraction! This can cause no end of consternation when accidentally used as a test, when should have been used, as can be seen in the first two highly counter-intuitive examples below:
"FALSE" (Surprise! It’s because means which is 0 which is a FALSE!) "TRUE" (Surprise! It’s because means which is 1 which is a TRUE!) "TRUE" (because means '1 is equal to 1' which is TRUE.) "FALSE" (because means '2 is equal to 1' which is FALSE.)Therefore, remember to use when you want to TEST for equality! Only use in mathematical equations! YOU HAVE BEEN WARNED.