How to Enter Answers in WeBWorK
Addition 
+ 
a+b
gives 
Subtraction 
 
ab
gives 
Multiplication 
* 
a*b
gives 
Multiplication
may also be indicated by a space or juxtaposition, such as 2x,
2 x,
2*x,
or 2(x+y). 

Division 
/ 
a/b
gives 
Exponents 
^ or ** 
a^b
gives as does a**b 
Parentheses, brackets, etc 

(...),
[...], {...} 
Syntax for entering expressions
·
Be
careful entering expressions just as you would be careful entering expressions
in a calculator.
·
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 an
explicit multiplication symbol makes things clearer.
·
Use
parentheses (), brackets [], and curly braces {} to make your meaning clear.
·
Do
not enter 2/4+5 (which is 5 ½ )
when you really want 2/(4+5) (which is 2/9).
·
Do
not enter 2/3*4 (which is 8/3) when you really want 2/(3*4) (which is 2/12).
·
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 is always good practice to use parentheses
when entering functions. Write sin(t) instead of sint or sin t.
WeBWorK has been programmed to accept sin t or even sint to mean sin(t). But sin
2t is really sin(2)t, i.e. (sin(2))*t. Be careful.
·
Be
careful entering powers of trigonometric, and other, functions. You write (sin(t))^2 for the square of sin(t), and never sin^2t.
·
For
example for the expression , 2+3sin^2(4x) is wrong. You should enter: 2+3*(sin(4*x))^2. Why does the last expression work?
Please
Excuse My Dear Aunt Sally
Operations
in parentheses are always done first (4*x) and then (sin(4*x))], next all exponents are taken,
giving (sin(4*x))^2, next all multiplications and
divisions are performed, giving 3*(sin(4*x))^2. Finally, all additions and
subtractions are performed, giving 2+3*(sin(4*x))^2.
·
Remember
that multiplication and division have the same precedence and there are no
universal rules as to which should be done first in the absence of parentheses. WeBWorK and many computers read
things from left to right, so 2/3*4 means (2/3)*4=8/3. But some other computers will read 2/3*4 as 2/(3*4)=1/6.
The same lack of consistent rules
concerns powers, expressions like 2^3^4.
The only way to insure that you
are entering what you want to enter is the use of parentheses!!!
·
Use
the Preview Button to see exactly how your entry appears
to the system. For example, to tell the difference between 1+2/3+4 and [1+2]/[3+4]
click the Preview Button.
·
If
a problem calls for a decimal answer, give at least four decimal digits, or as
many as the problem specifies. For example, write 2.3453 instead of 2.34.
Intervals in WeBWorK
What is the
domain of ? One answer is x>=0 (x
is greater than or equal to 0). The best way to enter this in WeBWorK is by using interval notation: [0,infinity).
Other
intervals:
(2,3] is
the set .
(infinity,5) is
the set .
(infinity,
infinity) is the set of
all real numbers.
(2,3]U[4,5) is the set . (This is a union of two intervals and can be very important.)
Mathematical Constants Available In WeBWorK
pi This
gives π ≈ 3.14159265358979.
So cos(pi) is –1.
e This
gives e ≈ 2.718281828459045. So,
ln(e*2) is 1 + ln(2)
Scientific Notation Available In WeBWorK
2.1E2 gives 210
2.1E2 gives 0.021
aEb gives
Cube roots and nth Roots
x^(1/3) gives , the cube root of x
x^(1/n) gives , the nth root of x
x^(p/q) gives
Mathematical Functions Available In WeBWorK
abs( ) , the absolute value
cos( ) the cosine
function. Note: the cosine function uses
radian measure
sin( ) the sine
function. Note: the sine function uses
radian measure
tan( ) the tangent
function. Note: the tangent function
uses radian measure
sec( ) the secant
function. Note: the secant function uses
radian measure and
exp( ) the exponential
function, e^{x}
log( ) The natural logarithm
function. Note that this is NOT the
common log function from precalculus.
ln( ) Another, more
common name for the natural logarithm,
logten( ) The common logarithm or log
base 10,
arcsin( ) The inverse sine
function. asin( ) is another name for arcsine.
arccos( ) The inverse cosine function. acos( ) is another name for arccosine.
arctan( ) The inverse tangent function. atan( ) is another name for arctangent.
sqrt( ) The square root function
sgn( ) The sign function —
step( ) The step function — (0 if x < 0, 1 if x
>= 0)
fact( ) The factorial function (defined only for nonnegative integers),