Concave Definition and 196 Threads

Homework Statement f:R->R, c' prove that f is concave iff f(x*)+(x-x*)f'(x*)>=f(x) Homework Equations assume the function is only once differentiable The Attempt at a Solution i have no idea how to approach this question...:confused:

Homework Statement What is the relative size, orientation, and type of image from an object placed at the centre of a concave mirror? Homework Equations I drew a ray diagram for this. The Attempt at a Solution The image will be erect, the same size and real. That seemed...

Homework Statement "Please draw an image for a double concave lens with the object paced between the lens and the focal point. Remember to show all the required rays, their direction, and the focal point of your lens" Homework Equations no equations needed. The Attempt at a...

Can anyone explain to me the procedure that one would follow to you find the focal length of a concave lens using a convex lens? Thanks.

ok my doubt is wen i look at a concave mirror(behind focus of mirror) i can see image of my face inverted inside the mirror,,,why does this hapen?? acc to mirror laws i shud get a real image tht too not inside the mirror but outside it! y do i observe an inverted virtual image in case of...

Homework Statement http://img215.imageshack.us/img215/8457/physicsol4.jpg Homework Equations n1sin01=n2sin02 1/f = (n-1)(1/r1-1/r2) The Attempt at a Solution I'm really jus confused with this problem I don't really see where to start. I'm assuming the fish bowl is a...

lenses and mirrors?? hi all, i was wondering what would happen if a convex lens and a concave mirror were set up one after another, the convex len being first to receive the light. how would this work in spot lights? i don't see howa spot light can have a tightly focused spot on a stage, i...

[SOLVED] Moment of inertia for Concave Polygon While working on a simulation I ran into this problem. I'm trying to calculate the moment of inertia for a concave polygon. The polygon is made of N vertices (Also the edges are straight lines). I've done a bit of researching however I've only...

Homework Statement Let f(x) be concave, how do you describe its set of absolute maxima Homework Equations The Attempt at a Solution

Im trying to figure out the best way to heat a about a bottles worth of water, my idea was to get a concave mirror and focus it onto some small radiator like a heater core. The thing is I can't find a large concave mirror, so I was thinking about using a satalite dish but I can't think of a way...

Homework Statement A concave mirror (f = 44 cm) produces an image whose distance from the mirror is one-fourth the object distance. (a) Determine the object distance. cm (b) Determine the (positive) image distance. cm Homework Equations 1/do +1/di =1/f do=object...

Homework Statement A person 1.62 m tall wants to be able to see her full image in a plane. a) What must be the minimum height of the mirror? b) How far above the floor should it be placed, assuming that the top of the person's head is 15 cm above her eye level? Draw a ray diagram...

Homework Statement Focal length of a concave mirror. This was an experiment, done in class. I was required to collect a light globe:(of course with a power source) for the object, paper:screen/image, and a concave mirror. I created the images, of the globe filament, to the screen...

Homework Statement Determine whether the curve x = 3t^2, y = e^2t+1 is concave up or concave down at the point (3, e^3) thanks for any help with this one. Homework Equations The Attempt at a Solution know i need to take the double derivative. Also that would be 6 and...

A concave mirror has a radius of curvature of 0.5 m. At what position should and object be placed to produce an upright virtual image that is 3.0 times as large as the object? I have just no clue for this question,, but I have to understand it T.T can any1 help me please>..

As the object is moved along the principle axis toward the vertex of a concave mirror, the type of image changes. Where does the change in type of image occur? Explain why, in terms of the path of the light rays. I just don't know what it means, can you guys help me with this question?... I...

Homework Statement How can I show that h(x)=[g(x)]^2 is concave upward on an interval if we know that g is positive and is concave upward on the same interval? The attempt at a solution I know that that g''(x)>0 since it concaves up. But after this step, I'm lost on proving this question...

A spherical mirror is polished on both sides. When used as a convex mirror, the magnification is +1/4. What is the magnification when used as a concave mirror, the object remaining the same distance from the mirror? I started with: mconvex = 1/4 mconcave = ? doconvex = doconcave...

A 1.0 cm high object is situated 11.0 cm in front of a concave mirror that has a radius of curvature of 8.00 cm. Using a ray diagram drawn to scale (the mirror must be drawn to scale): (a) measure the location of the image: 6cm (infront of the mirror) (b) measure the...

This is much longer than the normal post, so please bear with me. I was wondering if anyone here knows the complete derivation of Ideal Gas Law (or can recommend a book that describes it clearly and fully), who can tell me whether its conclusions are valid for any shape of gas particle, and...

Homework Statement An object is placed 6 metres from a convex lens of focal length 30cm. A concave lens of focal length 5cm is then placed 20 cm from the concave lens, on the side distant from the object. Determine the position, magnification and nature of the final image formed (to solve...

There are three of us in our physics class... and we are having trouble with concave parabolic mirrors. We use Saxon's physics book, and he does a horrible job at explaining how to solve, or even set up, the problems. If anyone could give advice or insight, it would be greatly appreciated...

i need to find the cardinality of the set of all concave polygons. i know that each n-polygon is characterized by its n sides, and n angles, but i didn't find its cardinality, for example we can divide this set to disjoint sets of: triangles,quandrangulars, etc. we can characterize the...

hiya I'm having some problems understanding concave mirrors and their reproduction of actual object. 1) Can you show me some proof as to why all rays of light from the object converge at the same point ( image point )? 2) I'm having hard time understanding how person...

"A concave mirror of focal length 1m is used to magnify an object by a factor of 4. Where is the object in relation to the pole of the mirror?" Heres what i did: \begin{array}{c} M = \frac{v}{u} \\ \therefore 4 = \frac{v}{u} \\ \therefore v = 4u \\ \end{array}...

we used a concave mirror and a candle for an experiment when the candle wa placed between the vertex and the focus of the mirror (f=12.7cm) a virtual image appeared behind the mirror. We measure the image distance approximately by pointing a finger towards where the image might be and got...

we used a concave mirror and a candle for an experiment when the candle wa placed between the vertex and the focus of the mirror (f=12.7cm) a virtual image appeared behind the mirror. We measure the image distance approximately by pointing a finger towards where the image might be and got...

Concave mirror experiment We did an experiment with a concave mirror Concave mirror was placed on optics bench and a candle was placed at designated spots. A screen was used to see where the image was projected. But a strange thing happened. When the object was placed at the focal point, image...

We did an experiment with a concave mirror Concave mirror was placed on optics bench and a candle was placed at designated spots. A screen was used to see where the image was projected. But a strange thing happened. When the object was placed at the focal point, image was projected on the...

problem: Use the graphing strategy to sketch the graph of y=(4x)/(x^2+1). check the intervals where it is concave up and where it is concave down. Then graph it. please use sign charts. to find this we have to first find y''. so I used the quotient rule twice to get this y'' = (8x^5 - 16x^3...

Hi Why is that you can see a REAL image in a concave mirror when you are looking into the mirror? i tried searching the answer on the net but could not find the answer. please help thanx in advance.

# A convergent beam is incident on a concave lens as shown in figure. Which of the following is not correct? a) The image formed is real b) The image formed is virtual c) The image formed is erect d) The image formed is magnified I solved it in the following way: Let f be the focal...

# A convex lens of focal length 10 cm forms a real image of an object placed at a distance of 20 cm from it. Midway between the convex lens and the position of the image a thin concave lens is introduced. The image formed now is at a distance of 5 cm away from the earlier position. What is the...

A concave mirror has a focal length of 10 cm. what is its radius of curvature?:eek: i have absolutely no idea how to solve this, please help:cry:, any advice is greatly appreciated:smile:

how can you tell when the image will become real or virtual in a concave mirror, the distance?..i'm not sure thanks in advance *edit* oh i think i know..is it the magnification, if the magnification is more than 1 then that means its virtual since it would be upright and a bigger image...

Hello everyone< i think I'm on the right track but now I'm stuck. Here is the problem: A concave shaving mirror has a radius of curvature of 37.0 cm. It is positioned so that the (upright) image of a man's face is 2.50 times the size of the face. How far is the mirror from the face? Here is my...

Hello everyone, I tried a problem on concave mirros and i have no idea why this is wrong. I was given enough info but still didn't like it. Here is the problem: Spherical mirrors. Object O stands on the central axis of a spherical mirror. The table gives object distance p, the type of...

Hey eveyone, I have a concave mirror and an object x distance away from the mirror. I am wondering if anyone knows where you measure from in order to determine how far away the object is from the mirror. Is it from the object to the center of the concave mirror? Thanks, ccflyer

Ok, there's something I just don't understand. I know that to find the height of an image (hi), you need to use the magnification equation m = -di/do = hi/ho. And for this question, the focal length (f), distance of object (do), and distance of image (di) are given. Now, if I want to find the...

I am trying to figure out how those double concave mirror set ups work to create an image above the mirror. Does anyone know what I am talking about? You have 2 [spherical] concave mirrors, both with the same radius of curvature (and thus the same focal length), one facing up, and the other...

If I had a graph of f', would the intervals where f' is decreasing be the same as the intervals where f is decreasing? For example, the graph of f' is degreasing from -1 to 0. Is f decreasing from -1 to 0 also? With the same graph of f', how would you know on which intervals f is concave up...

A converging lens (convex) and a concave mirror, both of focal length 5.0 cm, are arranged with their axes in line. The lens and the mirror are 10.0 cm apart and a candle is placed 3 cm infront of the mirror. By using a ray diagram or some other metho, find the location of all the images...

Well, here is the problem: A girl has her 2-cm high eye 12 cm directly in front of a concave mascara mirror or focal length 18 cm. Where is the object located, and what is the magnification? I'm really lost on this one. EDIT: Sorry, I just realized this would be better suited for the...

if a double concave mirror with a focal length f = -20 inches is used , where does the image seem to be located , if the image is 30 feet away from the lens first i converted the 30ft to inches and got 360inches used formula 1/p + 1/q = 1/f .0028 + 1/q = -.05 1/q = -.053 q = -18.9...

Problem 8. A concave amkeup mirror is designed so that a person 28.7 cm in front of it sees an upright image ata distance of 51.1 cm behind the mirror. What is the radius of curvature of the mirror? Answer in cm. Note: What is the radius of curvature formula? Problem 19. A convex...

Can someone get me started on this, I know how to work a diverging lens and a concave mirror, just not together. The problem: A concave mirror with a radius of curvature of 20.0 cm is placed 25.0 cm from a diverging lens with a focal length of 16.7 cm. An object is placed midway between the...