BQ GIAO DUC VA DAO TAO DAI HQC HUE<br />
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Hp vd tln thi sinh:<br />
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danh; Sii Uao<br />
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(Dqt xV rul TUYEN sINHsAu DAIHgc xau 2012 l)<br />
Mdn thi: TOAN CHO VAT LV (Danhcho caohqc) Tl4digian ldm bdi.' 180 phut Ciu l. Tinh V' (i f (r)),trong do F - xi + yj + ti ld b6nkinh vecto,r : lil, chi f (r) la ham v6 hucrng phUthudcvdo r vd V ld to6ntu Nabla. r ' 1 i \ \ grad va r: Ap dung kOtqua tr6n dti tintr orv [ai" (;)] \,,/ Cflu 2. GiAibdi todn (urt:uxx+2, 00<br />
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: 1u@,0)0, fr(0, t) : 0,<br />
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ut(x,o)=0, u(n,f) : 0,<br />
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o 0,<br />
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cua bdne cach ddI u : v * w trong do w - w(x) la nghiQrn bdi todn {*"--2, tw(0) 0, 01x1n w(n) - 0.<br />
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CAu 3, Cho mQtthanh m6ng, ddng chht,chi6u diril; dAux - 0 cua thanhdugc git o nhiQtd0 kh6ng d6i bing ?nr, dAu x = t dugc giti o nhiQtd0 khdng ddi bdng ?"r.Tim ph6nbd nhiqt tr€n thanh hic f > 0? Bi6t ring nhiet dQban dAucua thanhbing 0. CAu 4. Tim nghi€mu(x,y) cua phuong trinh Laplaceu*, * ,X, = 0 trong hinh cht nh4tD - {(x,y) € IRz[0< x I Tr,0< y