Answer:
The Taylor series of f(x) around the point a, can be written as:

Here we have:
f(x) = 4*cos(x)
a = 7*pi
then, let's calculate each part:
f(a) = 4*cos(7*pi) = -4
df/dx = -4*sin(x)
(df/dx)(a) = -4*sin(7*pi) = 0
(d^2f)/(dx^2) = -4*cos(x)
(d^2f)/(dx^2)(a) = -4*cos(7*pi) = 4
Here we already can see two things:
the odd derivatives will have a sin(x) function that is zero when evaluated in x = 7*pi, and we also can see that the sign will alternate between consecutive terms.
so we only will work with the even powers of the series:
f(x) = -4 + (1/2!)*4*(x - 7*pi)^2 - (1/4!)*4*(x - 7*pi)^4 + ....
So we can write it as:
f(x) = ∑fₙ
Such that the n-th term can written as:

Answer:

Step-by-step explanation:
We want to find the sum of

We can rewrite this as

This becomes;

Recall that;

This implies that;

Combine like terms:

Answer:
Sue would have taken 15 hours to sew all the costumes.
Step-by-step explanation:
In 10 hours, Sue sewed 5 costumes (1 every 2 hours).
Sue= 5 costumes
Sue sewed in 10 hours, twice as many costumes as Anne in 16 hours. Then 5 is twice costumes than Anne produced. Therefore, Anne sewed 2.5 costumes.
Anne: 2.5 costumes
In total they had to sew 5+2.5= 7.5 costumes. Then Sue would have taken 7.5*2= 15 hours to sew them all.
5+0=5 is the property of zero
The property of zero is when u add 0 to n so that n stays n