A: You get stepbystep solutions for derivatives and indefinite integrals
in a completely automatic way, with each step explained.
You also get stepbystep determinants and matrix inverses.
And you can get the graph of a function automatically!
A: You can get as many fully worked out solutions as you need.
After a while you'll master the basic computations and be free to understand the concepts. You'll have the confidence to tackle applications like related rates or volumes of revolution without fear.
It's like anything else: get a good foundation and build on it.
Yes, tutoring is now available. Email for information.
A: Derivatives are free! Enter your function in the derivative field and press Do it!
You get the second derivative as well as the first. You can take the second derivative with respect to a different variable.
Polynomial long multiplication and long division are also free.
Integrals are cheap. You need to get a password to do an integral. You can buy a $25 password for 900 solutions.

The same ideas apply to the curve sketching and stepbystep determinants and matrix inverses.
A: Yes, if they involve functions beyond freshman calculus, like Bessel or other advanced functions. But calc101.com can do any freshman derivative, up to the limits of the computer.
A: Again, calc101.com can only do freshman integrals. Out of nearly four thousand tests from four calculus books, there were a few calc101.com couldn't do. That's better than 99.9%.
To avoid bogging down the system with huge problems, a maximum of 50 steps are allowed and there is a time limit for each integral. You should be able to get the solution to almost any integral from a standard calculus book without a problem.
If you don't get an answer to an integral that came from a calculus book, check your input carefully to make sure you are following the right input format.
It is easy to type in simplelooking integrals that cannot be done by anyone, anywhere. Probably the random example x^2 tan[x+1/x] is like that. You are never charged for a tough integral that calc101.com can't do.
Over time mathematicians have figured out how to solve many classes of advanced integrals, but only by going far beyond the likes of trig or hyperbolic functions.
A: Sure. These functions cannot be integrated in terms of elementary functions: e^x^2, sin[x]/x, cos[x]/x, 1/ln[x]. In fact their integrals are used to define new advanced functions.
A: Sure; use y[x] for a function of x. For example, input x^2 + y[x]^2. (If you only enter x^2 + y^2, y will be treated as a constant so its derivative will be zero.)
Not directly, sorry. First find the indefinite integral using calc101, then substitute the upper and lower limits of integration by hand and subtract. This will work if the function is continuous on the interval. Unfortunately checking that a function is continuous is very hard to program, as is finding the limit of a function.
A: For a derivative the answer will be right 100% of the time, guaranteed.
For an integral, calc101.com does a careful internal check before showing a solution. If it is wrong you will get a message saying that calc101.com could not do the integral. Your account will not be debited unless the solution is correct.
Very rarely, in spite of many checks, it may happen that calc101.com gives a wrong answer for an integral. If you notice an example, please send email!
Of course, if you input x sin[x]^2 but you meant x sin[x^2], you will get an answer and your account will be debited. calc101.com can't tell the difference between what you mean and what you type.
A: Currently the most common input mistake is forgetting brackets for compositions of functions, like sin[sqrt(x)] (wrong) instead of sin[sqrt[x]] (right). Your account will not be debited for mistakes like these, but they slow you down.
A: Sure. Print your results or save them to your machine's hard drive for future reference.
A: If the answer is too big, your browser may have trouble displaying it. Try a variation of the integral by lowering a power, for example.
Another possibility is that some part of the system is down. Wait a while before trying again. It's good that you tried more than once, though.
A: The integrals of sec[x] and a few other functions come up almost as often as the integrals of sin[x] and cos[x]. They are derived by tricks that take a few steps. So these special trig cases are separated out to avoid cluttering solutions.
A: The derivations of reduction formulas are also shown separately. To derive a reduction formula you usually need to do integration by parts twice and then solve for the original integral with a bit of algebra. calc101.com simply applies a reduction formula the way people usually do.
A: You can get partial fraction decomposition at partial fractions for free. The program was written by guest programmer Sam Blake.
A: Sure. calc101.com can integrate sin[a x] and many other similar cases. By the way, make sure you separate the parameter from the variable by a space or an asterisk * to indicate multiplication: sin[a x] and sin[a*x] will work but sin[ax] won't work.
A: Yes, some integrals with a symbolic parameter will fail. For example, a reduction formula works powers down from n to either n1 or n2. For calc101.com to be able to finish, the number n has to be an actual positive integer, not left as a symbolic parameter.
You can try any integral knowing that your account will not be debited if calc101.com can't do it. If an integral doesn't work with a parameter, you can try to find a general pattern by doing several examples with specific values of the parameter.
A: In principle variables and functions could be anything, but in practice there are very confusing choices and some technical limitations. Therefore not all letters are allowed.
Multiplication is indicated by a space or an asterisk: b sin[x] or b*sin[x]. However it is a very common mistake to run variables and functions together incorrectly, like bsin[x] (wrong!). This kind of bad input can lead to a lot of confusion!
The solution adopted in calc101 is to only allow two kinds of functions. First, the standard elementary functions like sin[x], log[x], and sqrt[x] are allowed. Second, calc101 can also handle symbolic unknown functions, so expressions like f[x], y[t], and g[z] are also allowed.
That blocks out typical typing mistakes like bsin[x], so you won't be charged for something that you probably don't want.
Parameters are also restricted to be a single letter. So b sin[c x] is fine, but mu sin[theta] is not alloweduse M sin[t] instead. The number pi (3.14159...) is allowed, though.
You can index parameters; for example, a[2] and k[3] are fine.
A: You can use these letters as the variable of integration, parameters or function names:
a, b, c, , e, f, g, h, i, j, k, l, , , o, p, q, r, s, t, , , w, x, y, z,
A, B, , , E, F, G, H, , J, K, L, M, , , P, Q, R, S, T, U, V, W, X, Y, Z.
exception: The letter e is the base of the natural logarithms (2.71828...). You can use e in functions, like x e^x^2, but not as the variable of integration in the "with respect to" field, or as the name of an unknown function.
The number pi (3.14159...) is similar.
A: Avoid d, m, n, u, v, which are used by calc101 and C, D, I, N, O which have a meaning in Mathematica.
A: Even though calc101.com does the steps to follow what a human would usually do, it may not solve a problem exactly like your textbook or teacher. That's because there may be a choice of different methods at various points. If the problem is simple enough, the answers will usually look the same.
A: calc101.com makes the valid assumption that variables are in domains that allow absolute values to be ignored. This keeps the work simpler.
This assumption is legitimate, according to Remark 1, p. 239, Calculus and Analytic Geometry, Fourth Edition, by George B. Thomas Jr., published by AddisonWesley, 1968. We won't go into the details here. Essentially the idea is to define the principal values of these functions for negative values of x to be in appropriate intervals. By the way, the functions arccsc[x] and arcsech[x] are similar to arcsec[x]. Of course, none of this matters if x is positive.
A: This site supplements text books by giving you stepbystep solutions to the two basic operations of calculus. There are hundreds of books and web sites that explain calculus. Calc101.com does calculus.
A: The one that has an extra line through it? That's e (approximately 2.71828...), the base of the natural logarithms. It is displayed that way in output. You input it as e.
A: The most likely reason is that you typed in something that you didn't intend. For instance, if you enter x / x^2 + 1 when you mean x / (x^2 + 1), it might look like calc101.com made a silly mistake.
calc101.com will process any input that is in the correct syntax. It doesn't know you meant something else. Not using the right input format, mistyping, or miscopying from your book may lead to puzzling results.
A: calc101.com uses a system of completely automatic computer programs. It doesn't need any human intervention to work. That means you can get an answer any time of the day, seven days a week.
The program that takes derivatives has 15 rules. They more or less correspond to the usual rules you learn in calculus, like the product rule and the chain rule. The program that does integration is much more complex, with more than 300 rules. For integrals, the main problem was to arrange the rules so that the right one worked at the right time.
The stepbystep programs in calc101.com are written in Mathematica, a software system with thousands of mathematical, graphics, numerical, and programming functions. Mathematica includes derivatives and integrals, not to mention solvers for algebraic and differential equations, and much more.
A: To make solutions clear, natural, and as easy to follow as possible. Here's how.
A: To raise your calculus grade by 10%.
Good luck with calculus and please help spread the good word about the site!