diff --git a/src/sol-kilo.typ b/src/sol-kilo.typ index 662ae55..050ad04 100644 --- a/src/sol-kilo.typ +++ b/src/sol-kilo.typ @@ -23,7 +23,7 @@ $ z_1 &= 10 (cos 90 degree + i sin 90 degree) \ z_3 &= 10 (cos 330 degree + i sin 330 degree). $ Of these three answers, we want the one -whose real and imaginary part are both negative. +whose real and imaginary parts are both negative. Only $z_2$ works; in rectangular form it is $ z_2 = 10 (- sqrt(3) / 2 - i 1 / 2) = #boxed[$ - 5sqrt(3) - 5 i $] $ (and this is the only possible example). @@ -49,7 +49,7 @@ the other one is $#boxed[$ lambda = 5 $]$. To get the eigenvector, write $vec(x,y)$ so that we need $ M vec(x,y) = 5vec(x,y) ==> - cases((1-5)x + y = 0, -4+(6-5)y=0) ==> y=4x. $ + cases((1-5)x + y = 0, -4x+(6-5)y=0) ==> y=4x. $ So an eigenvector for $5$ is $#boxed[$ vec(1,4) $]$ (or any nonzero multiple of it). #h3[Solution using trace and determinant shortcut] @@ -83,7 +83,7 @@ $ x + y + z = b. $ In order for this to also pass through $(2,3,6)$, we need $b = 2 + 3 + 6 = #boxed[$ 11 $]$. -It remains to calculate the distance from $(0,0,0)$ to the plane $x+y+z=11$. +It remains to calculate the distance from $(1,2,3)$ to the plane $x+y+z=11$. If you use the point-to-plane formula (@sec-distance-plane) for this, you get $ abs(1+2+3-11) / (sqrt(1^2+1^2+1^2)) = #boxed[$ 5/sqrt(3) $]. $ @@ -214,8 +214,8 @@ $ int_(x=0)^1 int_(y=x)^1 int_(z=y)^1 e^(z^3) dif z dif y dif x &= int_(z=0)^1 int_(y=0)^z int_(x=0)^y e^(z^3) dif x dif y dif z \ &= int_(z=0)^1 e^(z^3) int_(y=0)^z int_(x=0)^y 1 dif x dif y dif z \ &= int_(z=0)^1 e^(z^3) int_(y=0)^z y dif y dif z \ - &= int_(z=0)^1 e^(z^3) z^2/2 dif y dif z \ - &= 1/6 int_(z=0)^1 e^(z^3) 3z^2 dif y dif z \ + &= int_(z=0)^1 e^(z^3) z^2/2 dif z \ + &= 1/6 int_(z=0)^1 e^(z^3) 3z^2 dif z \ &= 1/6 [e^(z^3)]_(z=0)^1 = #boxed[$ (e-1)/6 $]. $ == Solution to @exer-mf-7 (curl) @@ -257,8 +257,8 @@ Given $cal(S)$, we add two lids, $cal(S)_"top"$ and $cal(S)_"bottom"$. The top lid is the flat surface given by $z = 9$ and $x^2+y^2 <= 100$, with normal vector oriented upwards. The bottom lid is the flat surface given by $z = 7$ and $x^2+y^2 <= 100$, -with normal vector oriented outwards. -Finally, let $cal(T)$ denote the cylinder $1 <= z <= 2$ and $x^2 + y^2 <= 100$, +with normal vector oriented downwards. +Finally, let $cal(T)$ denote the cylinder $7 <= z <= 9$ and $x^2 + y^2 <= 100$, which is enclosed by $cal(S)$, $cal(S)_"top"$, $cal(S)_"bottom"$. Then the divergence theorem states that $ iiint_(cal(T)) nabla dot bf(F) dif V