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junior college 1 | H2 Maths
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I use the sine rule but i'm unable to find the length of DC. Pls help me, thanks!
Date Posted: 7 years ago
Views: 359
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Pls verify...
You may change the way I presented the working, the DC length... A bit messy...
You may change the way I presented the working, the DC length... A bit messy...
Date Posted:
7 years ago
So can i use the sine rule to find DC?
We don't know the length of AB and AC, sine rule can't be used...
But i find the angle DAC first. Then i use h/sin(pi/4)+x=DC/sin (pi/4)+x to find DC. Can it be accepted?
I know your mistakes now :
1) the x is part of the angle, it cannot be put outside of the sine, sin(pi/4 +x) should be the right way to write
2) the remaining angle DAC is pi/2 - (pi/4 + x) = pi/4 - x, the way you write is wrong
You can use sine rule in this case, then use sin(A+/-B) expansion to expand sin(pi/4+x) and sin(pi/4-x)...
1) the x is part of the angle, it cannot be put outside of the sine, sin(pi/4 +x) should be the right way to write
2) the remaining angle DAC is pi/2 - (pi/4 + x) = pi/4 - x, the way you write is wrong
You can use sine rule in this case, then use sin(A+/-B) expansion to expand sin(pi/4+x) and sin(pi/4-x)...
I expand already and i use the small angle approximation, but i can't still work out the working
I attached another photo, which uses your sine rule, it goes back to the same working, you check the photo...
Or you attached your working, I check your working...
Or you attached your working, I check your working...
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Date Posted:
7 years ago
I understand now. Thanks for your explanation!
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