@Nikol 

restart;
with(Statistics):
X := RandomVariable(Poisson(200.)):
F:=CDF(X, t):
a:=evalf[10](eval(F, t=50.)):
b:=evalf[20](eval(F, t=50.)):
a/b;
                        9.999999997 * 10^9 

@MathStudent0807 In the help page there is the surface integral of the function f(x,y,z) = y^2, over the sphere centered at <0,0,0> and having the radius r.

with(VectorCalculus):
SurfaceInt( y^2, [x,y,z] = Sphere( <0,0,0>, r ) );

Are you trying to say that your integral is much different?

Open the help page; type
?SurfaceInt

Note that you can open the help page as a worksheet, by clicking the 'WS' icon.
You will find there a very similar example; just edit it.

@tomleslie My remark is about the exact solution which is awful. It containe RootOfs for polynomials with degrees >30.

@acer You could also mention that for
expr := sin(x) - cos(32*x - 1/6*Pi);
solve(expr, allsolutions);
==> huge answer (length >1000000)
instead of a simple and easy to obtain:
{-1/93*Pi - 2/31*_Z1*Pi, 2/99*Pi - 2/33*_Z2*Pi}

For 
eq  := 2*exp(-exp(2*t)) + 4*t = 127

it will be (almost) impossible using fsolve to decide whether the solution is rational or not.

@rupsagar I don't see your desired result. Without it, it would be a waste of time to continue.

@rupsagar You forgot an example and the desired result.

@rupsagar Provide solution to what? If you use z(x) as above, the chain rule is automatic as shown.
If you want something else, provide a concrete example (include the desired result).

@mmcdara Yes, and all three of us know them. Anyway, the probability that someone knows the ode of the catenary but not its formula is low.

@mmcdara The "simpler" adjective is very relative:

restart;
Y := x -> (cosh(a*x)-1)/a:
L := x -> sinh(a*x)/a:
solve([L(x1)+L(x2)=140, Y(x1)=50, Y(x2)=70, a>0,x1>0,x2>0], explicit):
evalf(%);
#         {a = 0.09213375345, x1 = 26.14739561, x2 = 29.26983504}

Download involution-vv.mw

@jeffreyrdavis75 You should state clearly what you want to be proved, in correct Maple syntax (or at least a correct mathematical  formula).

@eager0626 
I have used a combination of Groebner[Basis], solve and fsolve(for polynomials).
I did it only because I wanted to know the exact situation, the results of fsolve and DirectSearch being confusing.
Knowing now that except for (a=0,b=0,u=anything)   there are exactly two solutions  (a0, b0, u0)  and  (-a0, b0, Pi+u0),  we may use fsolve which is very fast!

fsolve(eval(sys,sigma=0.5), {a=0.0001 .. 1, b=0.0001 .. 1,  Upsilon=-Pi..Pi});

       {Upsilon = 0.01767204623, a = 0.01542763525, b = 0.002577584538}

The solution set is infinite (even uncountable), e.g. a=0, b=0, Upsilon=arbitrary;  (actually Upsilon should be modulo 2*Pi). So, finding all of them numerically is out of the question.

If you really need all the solutions, you could convert the system into a polynomial one (e.g. using cos(Upsilon)=c, sin(Upsilon)=d, c^2+d^2=1) and call solve or (better) Groebner:-Basis.