plz help in mathematica

[eftenpuften]

hello everyone. i am very new on mathematica.I have 2 problem at first, i have to eavluate the numerical equivalent of tan(45/Pi+Pi/45) when i wrote on mathematica like this:

In[21]:=

Tan[45/Pi+Pi/45]

Out[21]=

\!\(Tan[45\/π + π\/45]\)

 

it gives me that one. can not i get a real number from this?It doesnt solve tangent.i tried Solve[..] or Evaluate[..] but both they didnt work. And secondly how can i find the are of the region enclosed by the curves : y+45(x+45)=0 and y-x^3/45+45=0 ? i really dont have any idea about this. thanks for your helps from now.. it is very urgent i hope someone could help me

[timo]

- To get a real number from an expression, use N[expression], in your case N[Tan[45/Pi+Pi/45]]. Alternatively, tell Mathematica that 45 is a real number by typing "45.0", instead.

- For the second one, if you're just looking for the approximate area, then how about plotting the curves? You want to transform the equations into a form y=... for that.

- If you want to use Mathematica to take a shortcut on your homework: Better screw the idea. It's usually more work to translate a problem to a computer than to do it by hand, that's especially true for homework problems which are designed to be easily done by hand.

- Generally, for the 2nd part, when the two curves enclose an area you'd assume them to meet twice, meaning there's two x-values [math] x_1, x_2 [/math] for which [math] y_1(x_1) = y_2(x_2) [/math] and [math] y_1(x_2) = y_2(x_2)[/math] respecitvely, where y1(x) and y2(x) means the two different curves.

[eftenpuften]

thank you so much atheist. i have done the first part. and for the second part i can do by myself but teacher wants it from mathematica. In normaly they must teach but they showed just a little part of mathematica. and they want the answers in printouts tomorrow. if they accept of course i can write by hand, but the homework is about mathematica if you can help for the second one too,i will be glad. i donno any function or anything else in this program. because my depertman is not mathematics lol. if you can write the full formulas or anything that can help me, i would be glad.

[timo]

- Rewrite both functions to y=f(x)=... .

- Plot both functions. You can type in "Plot" in Mathematica and then press F1 on the word to call the description of the command to find out how exactly it is used (note: you can also execute the samples in the help file directly by clicking on then and then executing them with shift+enter).

- Plotting the functions should give you an idea what the problem "looks like". It will also show that the two functions do not enclose any region at all. Reconsider your problem again from there.