MATH 150 Calculus I

A useful guide for students to input WeBWorK problems

Mathematical Symbols Available In WeBWorK

• + , –   for Addition, Subtraction.
• * for Multiplication. Also may use a space or juxtaposition, e.g. 2*x, or 2x, or 2 x. 2(3+4) is also valid.
• /  for Division.
• ^ or ** for exponentiation, e.g. 3^2 or 3**2.
• (   ), [], {} for grouping terms.

Syntax for entering expressions

• Enter expressions just as you would in a calculator. Recall the order of operations:
  • First to be evaluated is inside parenthesis.
  • Next is Functions (e.g. sin, cos, log)
  • Then Exponents, from right to left. 2^3^4 = 2^(3^4)
  • Next is Multiplication and Division, from left to right. 2/3*4=(2/3)*4
  • Lastly, Addition and Subtraction.
• Use the "Preview Answer" button to see exactly how your entry looks. To see the difference between 1+2/3+4 and [1+2]/[3+4], click the "Preview Answer" button.

Mathematical Constants Available In WeBWorK

• pi for 3.14159265358979…, e.g. cos(pi) is -1
• e for 2.71828182845905…, e.g. ln(e) is 1

Scientific Notation Available In WeBWorK

• 2.1E2 gives 210
• 2.1E-2 gives .021

Mathematical Functions Available In WeBWorK

• abs( ) The absolute value
• cos( ) Note: cos( ) uses radian measure
• sin( ) Note: sin( ) uses radian measure
• tan( ) Note: tan( ) uses radian measure
• sec( ) Note: sec( ) uses radian measure
• exp( ) The same function as e^x
• log( ) The natural log
• ln( ) Another name for the natural log
• logten( ) The log to the base 10
• arcsin( )
• asin( ) Another name for arcsin
• arccos( )
• acos( ) Another name for arccos
• arctan( )
• atan( ) Another name for arctan
• sinh( )
• cosh( )
• tanh( )
• sech( )
• sqrt( )
• sgn( ) The sign function, either -1, 0, or 1
• step( ) The step function (0 if x < 0, 1 if x >= 0)
• fact( ) The factorial function (defined only for non negative integers)

Useful hints and Common problems

• Use “(  )” to make your meaning clear. You can also use [  ] and { }.
• Entering big quotients with square brackets, e.g. [1+2+3+4]/[5+6+7+8], is a good practice.
• Be careful when entering functions. It's always good practice to use parentheses when entering functions. Write sin(t) instead of sint or sin t. WeBWorK is smart enough to accept sin t or even sint. Note that sin 2t is really sin(2)*t. Be careful!
• Understand that sin^2 t is not a valid way to enter “the square of sin of t”, which is (sin(t))^2. Why? Because sin is a function, and functions require an input.  For example 2+3sin^2(4x) is wrong. You need to enter something like: 2+3(sin(4x))^2 or 2+3sin(4x)^2. Why does the last expression work? Because things in parentheses are always done first, i.e. (4x), next all functions, such as sin, are evaluated [giving sin(4x)], next all exponents are taken [giving sin(4x)^2], next all multiplications and divisions are performed [giving 3sin(4x)^2], and finally all additions and subtractions are performed [giving 2+3sin(4x)^2].
• Sometimes using the * symbol to indicate multiplication makes things easier to read. For example (1+2)*(3+4) and (1+2)(3+4) are both valid. So are 3*4 and 3 4 (3 space 4, not 34) but using a * makes this clearer. Use the "Preview Answer" button to see if you wrote it correctly.
• 2/4+5 (which is 5.5) is not 2/(4+5) (which is 2/9). Use the "Preview Answer" button to see if you wrote it correctly.
• 2/3*4 (which is 8/3) is not 2/(3*4) (which is 2/12). Use the "Preview Answer" button to see if you wrote it correctly.

Revised 12/09/04
By Don Short, dshort@sciences.sdsu.edu