# Each cell is evaluated individually, by either clicking the 'evaluate' link
# below the cell, or by pressing 'shift + enter'
2+7
integrate(x^3,x)
show(integrate(x^3,x))
diff(1/(1+x^2),x)
# Now let's look at some 3-dimensional graphs.
# We first have to specify which variables we'll be using.
x,y,z=var('x,y,z')
# In the plane, we're all familiar with the graph of y=x^2
plot(x^2,(x,-5,5))
# When another dimension is introduced, the same equation produces a
# PARABOLIC CYLINDER:
plot3d(x^2, (x,-5,5), (y,-5,5))
# If we introduce the third variable into the equation,
# we'll get the three-dimensional version of a parabola.
# A PARABOLOID is the graph of f(x,y) = ax^2 + by^2
plot3d(x^2 + y^2, (x,-8,8), (y,-5,5),aspect_ratio=(10,10,1))
# We can even graph equations that can't be written as functions
implicit_plot(x^2 + y^2 == 9, (x,-5,5), (y,-5,5))