From the given recurrence, it follows that

and so on down to the first term,

(Notice how the exponent on the 2 and the subscript of <em>a</em> in the first term add up to <em>n</em> + 1.)
Denote the remaining sum by <em>S</em> ; then

Multiply both sides by 2 :

Subtract 2<em>S</em> from <em>S</em> to get

So, we end up with

Answer:
approximately 4.978%
Step-by-step explanation:
The probability of both happening is 3/13*11/51, or 33/663, or 11/221 (approximately 4.978%). Two cards are drawn one after the other with replacement from a pack of 52 cards.
Simplify by combing the real and imaginary parts of each expression.
5 + 6i
Arrange the expression into the a+bi form of a complex number.
5+ 6i
4 divided by 12 is 1/3.
So, she would sprinkle 1/3 of a gram on each cupcake.