ANSWER

EXPLANATION
The given problem is

This is defined if and only if

Even the given expression can be simplified to obtain:

The exclusion is

Answer:
a) 25.15
b)
x = 1
y = t
z = (4pi)^2 + t *(8pi) = 4pi(4pi + 2t)
c) (x,y) = (1, -2pi)
Step-by-step explanation:
a)
First lets calculate the velocity, that is, the derivative of c(t) with respect to t:
v(t) = (-sin(t), cos(t), 2t)
The velocity at t0=4pi is:
v(4pi) = (0, 1, 8pi)
And the speed will be:
s(4pi) = √(0^2+1^2+ (8pi)^2) = 25.15
b)
The tangent line to c(t) at t0 = 4pi has the parametric form:
(x,y,z) = c(4pi) + t*v(4pi)
Since
c(4pi) = (1, 0, (4pi)^2)
The tangent curve has the following components:
x = 1
y = t
z = (4pi)^2 + t *(8pi) = 4pi(4pi + 2t)
c)
The intersection with the xy plane will occurr when z = 0
This happens at:
t1 = -2pi
Therefore, the intersection will occur at:
(x,y) = (1, -2pi)
8 ÷ (7 - 9) * ( 4 + (-4) ) <--- notice that bolded part.
4 + (-4) = 4 - 4 = 0.
after that, you're pretty much dividing and multiplying by 0, so
whatever ÷ whatever * whatever * 0 = 0.
(x/5)-6=2
It depends by difference of. Difference between is more specific.