Calculate the sum of the series:

π²/3!-π^4/5!+π^6/7!-π^8/9!+π^10/11!....

To calculate the sum of the series, we need to take an infinite number of terms, each term being the expression with alternating signs: π²/3!, -π^4/5!, π^6/7!, -π^8/9!, π^10/11!, and so on.

To calculate this sum, we can use the concept of Taylor series. The Taylor series expansion of the function e^x is given by:

e^x = 1 + x + (x²/2!) + (x³/3!) + (x⁴/4!) + ...

Comparing this with our given series, we can see that it is the Taylor series of e^x with x replaced by π². Therefore, we can rewrite our series as:

e^(π²) = 1 + (π²) + ((π²)²/2!) + ((π²)³/3!) + ((π²)⁴/4!) + ...

Now, if we subtract 1 from both sides, we get:

e^(π²) - 1 = π² + ((π²)²/2!) + ((π²)³/3!) + ((π²)⁴/4!) + ...

Hence, the sum of our series is given by e^(π²) - 1.

Now, let's calculate the numerical value of this sum:

Using a calculator or computer software, we can evaluate e^(π²) by using the exponential function. The value of e to the power of π² is approximately 23.14069.

Therefore, the sum of the given series is approximately 23.14069 - 1 = 22.14069.