&$6$!,& 91/0 & & & & ( K / u X -I UI 2I w X -% U% 2% . u w < ! & & u ⋅ w = -I-%ZUIU%Z2I2% $039< • F 0 0 . ) & & & & & & u ⋅ w u $ w u , w 3! & & & & u w ) u × w 17 7 2 / & & & & •F /! u ⋅ w = w ⋅ u / • . 1% 3 2 91 & & ( / uX-IUI2I w X-%U%2%)θ= ) & & ( u w ! & & & u ⋅ w & & = u . w . cos θ& ≤ θ ≤ I'&\ w θ & ; u 8/3 F= / 0 =/ / / 5 2 =θ/ )!& ≤ θ ≤ I'&\ & & 5 u ⋅ w cos & & θ = &u ⋅ w& u .w & & = u . w . cos θ/ ! 8 =θ / ) & & $θ = / u w ) / θX (u&], w& ) 9 =! \ / ) /0 !I'&\→ →π ,0 3C/KN&\%π 3 + .= !5* :5 *:5 • 3+/=θ / )! & & u w & & & & θX&\ u w ) / &\XI u ⋅ w i& & & u bb w & u θ & w & & & & θXI'&\ u w ) / I'&\XOI u ⋅ w j& & & u bb w %J & w & & & & θXJ&\= u w ) u ⊥ w & & J&\X& u ⋅ w X& • & u & w & & &jθjJ&\=θi& u ⋅ w i& θ & u & & J&\jθjI'&\=θj& u ⋅ w j& & w θ & u $039< •9 ! & & u ⋅ w = 0 ! (C/ [ (F/ 1θXJ&\c@ 3!J&\X&d & & & & & & = 0 [ ! i ⋅ j = j ⋅ k = i ⋅ k = 0 & & & B / V- ! i XI&& j X&I& k X&&I & & & • / 0 0 / /! 0 ⊥ ∀u & & & & / ! u ⋅ 0 = 0 0 ⋅ u () A & / u & & & & & & & ≠ 0 w ≠ 0 u ⋅ w = 0 ⇔ u ⊥ w 02 / Q,$! & 7(5/ u & & & = 3i + 8k w = 4, ( 2, − 5 ) / w& ⋅ u& & & & ;( 1/ u !( u ⋅ u K& & & & = | u | 2 0( u ⋅ 0 = 0 & & & & & & >($ | u | X% | w | XKI%&\= / u w u ⋅ w J( / =/0 %KI;%IOI(%%O%0 =; & K((= / v X%IOI AB KIO%;L&OL & & L(5 / / v1 XIOI& v2 XI&I KI Q&5 $!# & & & 7( / ) !( v XIO%K w XLM%0( i & & j & & & & & !/1 )K - 7 u ⋅ w /0)0 ;(5/ u XII& w X&I&/ u ⋅ w 0 0 >($1 =/0 OIO%L;OLO%&(KO%I5 = /0 ; J(F;()/0 =,7 I&( ; ( K(B -= =;(%IK;KKM(&LI & L(( 1K&\= / u XI% & & & j & & & M(5/ a X%I b XZ%OM% c X%' / / a + b & 1 / c & − a N(5 = =/0 %IK;I&OI(OI%I & & O($= / u X%IOI v XIOIZ%0πbK 7G( / MIM;LK%(OKO%I)/0 = = & & & & & & & & 77(P/ / = + M 1 − LA = + I + % 1 + LA 1 W & & & & 7;(5 / w / u X%OIK w ⋅ u XOL% & 7>(5 / 7 / v X%OII 7J(F = =;( QMI%IK( AB ⋅ AC + BA ⋅ BC + CA ⋅ CB & & & & & & & & 7K(5 / / Y / YXM / 0 -F2 / ⋅ G XN G = %1 + KA & & & & & & 7L(5 / v -F22 v ⋅ v1 XI& v ⋅ v2 XOM v1 X%KOI & v2 XIOI% 7M(5 = !/1.K 91/A91:7NU & & & & & & & & 7N(5/ u XIO%OI v XOII w XOII u ⋅ v = (u + v ) ⋅ w & & & & & & & & 7O(( 8/ u Z v u O v Y u YXLY v YXK= u v 0N&\ & & k XLM\ k XJ&\J(M&K(QL( ± IM M(fONKg 7(C2 6;( ⋅ G XI>( ; N( ˆ X M ≅MI\= ;ˆ X %L ≅ME\ (ˆ X 2 ≅E%\O(OL7G( ; ⋅ ;( = & 77(fOK%g J NK 42 § © 7;(ONKOJ7>(C0 ¨ & I % · ¸ 7J(INJ7K(LK&OLK&7L(OIL& %¹ I 7M( -E&\7N(X%7O( KE IK ;. -3T + // 2)./8 #. :/ K%