
18th May 2013, 08:56 PM

#1 (permalink)
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anyone know how to solve this?
I m totally clueless
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19th May 2013, 06:22 PM

#2 (permalink)
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Re: anyone know how to solve this?
I'm interested in knowing how to solve this too! Seems like university/engineering mathematics.

 
19th May 2013, 06:37 PM

#3 (permalink)
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Re: anyone know how to solve this?
Idk anything about Phong illumination but I'm assuming the incident angle is equal to the reflection angle and the light ray that is reflected from the sphere and directly into the viewer at origin is the brightest, am I right?
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19th May 2013, 10:29 PM

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Re: anyone know how to solve this?
Originally Posted by Betakuwe Idk anything about Phong illumination but I'm assuming the incident angle is equal to the reflection angle and the light ray that is reflected from the sphere and directly into the viewer at origin is the brightest, am I right? hmm I guess u are right, so I have to find the point of intersection between the ray and the sphere?
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20th May 2013, 09:20 AM

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Re: anyone know how to solve this?
The full solutions to the problem. Hope it helps. Peace. 
 
20th May 2013, 10:52 AM

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Re: anyone know how to solve this?
Thanks! but is there a simpler way to get the answer without using LaGrange Multipliers as we haven being taught on that.
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20th May 2013, 12:32 PM

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Re: anyone know how to solve this?
vector is a gradient 1 slope. assuming brightest source will be the one ray that shines directly through the circle and at the origin of the circle, with radius of circle at 2, we will be looking at a line of length 2 stretching from the circle origin to the edge of the circle at a 45 degree angle.
with that, position at edge of circle will be:
x = 2sin45
y = 5  2sin45
btw, i cannot remember sin or cos, but it doesnt matter because 45 degree. hmm thought my answer will be same as whitecorp. maybe i dont understand the Phong thing correctly.
Last edited by workingtoohard; 20th May 2013 at 12:33 PM.

 
20th May 2013, 01:19 PM

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Re: anyone know how to solve this?
Originally Posted by workingtoohard vector is a gradient 1 slope. assuming brightest source will be the one ray that shines directly through the circle and at the origin of the circle, with radius of circle at 2, we will be looking at a line of length 2 stretching from the circle origin to the edge of the circle at a 45 degree angle.
with that, position at edge of circle will be:
x = 2sin45
y = 5  2sin45
btw, i cannot remember sin or cos, but it doesnt matter because 45 degree. hmm thought my answer will be same as whitecorp. maybe i dont understand the Phong thing correctly. wow thats amazing.
x = 2sin45
thats the same as sqrt 2
y = 5  2sin45
if its 5+2sin45 then its the same as his answer.
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20th May 2013, 04:21 PM

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Re: anyone know how to solve this?
Originally Posted by workingtoohard vector is a gradient 1 slope. assuming brightest source will be the one ray that shines directly through the circle Excuse me? Shining through?

 
20th May 2013, 05:41 PM

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Re: anyone know how to solve this?
Originally Posted by whitecorp The full solutions to the problem. Hope it helps. Peace. eh the last eqn is = 0
2*sqrt2  2*sqrt2 + 10  10 = 0 and not 20 leh
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Last edited by oldvirgin; 20th May 2013 at 05:45 PM.

 
20th May 2013, 10:02 PM

#11 (permalink)
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Originally Posted by whitecorp Excuse me? Shining through? for a viewer standing at origin, light have to shine through wat, else how he see. Posted via Mobile Device 
 
20th May 2013, 10:04 PM

#12 (permalink)
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Re: anyone know how to solve this?
ohhh... lol... origin. not center of circle. Posted via Mobile Device 
 
21st May 2013, 12:41 AM

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Re: anyone know how to solve this?
Originally Posted by oldvirgin eh the last eqn is = 0
2*sqrt2  2*sqrt2 + 10  10 = 0 and not 20 leh My bad, made a substitution error.
Here are the rectified workings for the final part:
Peace.
Last edited by whitecorp; 21st May 2013 at 01:06 AM.

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