[SOLVED] volumes... last week of calc
i was absent when we went over the volume section.
y= 1/x, x= 1, x= 2, y= 0,; about the x-axis
\int^{1}_{2} \pi \frac{1}{x} dx
i don't know what's next. can anyone inform me, please
[SOLVED] one last optimization problems
Homework Statement
find two positive numbers such that the sum of the number and its reciprocal is as small as possible.
Homework Equations
x+(1/x) = s
f' =1 + ln x
The Attempt at a Solution
lost
Homework Statement
find the dimensions of a rectangle with perimeter 100m whose area is as large as possible
Homework Equations
area = XY
100 = 2x + 2y
y= 100/4x
x(100/4x)
(400x - 400x)/16x^2
1/16x^2 = 0
The Attempt at a Solution
well...
am lost
[SOLVED] simple optimization problem
Homework Statement
find the dimensions of a rectangle with area 1000 m^2 whose perimeter is as small as possible
Homework Equations
perimeter = 2x + 2y
area = xy
1000 = xy
y= 1000/x
perimeter = 2x + 2(1000/x)
The Attempt at a...
y=2x^{sinx}
i know i should use the product rule within a chain rule. but how can i use chain rule with sinx
is the anwser
y=-2x^{cosx}
can anyone give me pointer to this easy problem and tell if am forgetting something.
[SOLVED] another chain rule: easy one
y=xe^{-x^2}
i have no i dea how to start.
f'= x^{x^2} or -2x^blah blah blah
just get me started and i'll promise you i will finish it myself
[SOLVED] first derivative: chain rule: easy for you guys
Y=E^(-mx)
f= E^x g= -mx
f'= E^x g'= o
E^(-mx) * 0(E^(-mx))
i think, not sure though
Y'= 0
which is wrong
someone help
Homework Statement
A high voltage power line carries a current of 110 A at a location where the Earth's magnetic field has a magnitude of .59 G and points to the north, 72 degrees below the horizontal. find the direction and magnitude of the magnetic force exerted on a 250-m lengh of wire if...