Skip to content

Commit

Permalink
24_SP_TA: fix
Browse files Browse the repository at this point in the history
  • Loading branch information
tiankaima committed Apr 17, 2024
1 parent 8ef4e39 commit 0ee593d
Showing 1 changed file with 4 additions and 4 deletions.
8 changes: 4 additions & 4 deletions 2bc0c8-2024_spring_TA/main.typ
Original file line number Diff line number Diff line change
Expand Up @@ -648,9 +648,9 @@ $
&quad integral.double_D y / (1+x^2+y^2)^(3 / 2) dif x dif y quad D=[0,1]times[0,1]\
&=integral_0^1 dif x integral_0^1 y / (1+x^2+y^2)^(3 / 2) dif y\
&=integral_0^1 dif x integral_0^1 (1 / 2 dif y^2) / (1+x^2+y^2)^(3 / 2)\
&=integral_0^1 -(1+x^2+y^2)^(-1 / 2)|_0^1 dif x\
&=integral_0^1 [-(1+x^2+y^2)^(-1 / 2)]_0^1 dif x\
&=integral_0^1 -1 / sqrt(2+x^2) + 1 / sqrt(1+x^2) dif x\
&=-ln(x+sqrt(2+x^2)) + ln(x+sqrt(1+x^2))|_0^1\
&=[-ln(x+sqrt(2+x^2)) + ln(x+sqrt(1+x^2))]_0^1\
&=-ln(1+sqrt(3)) + ln(1+sqrt(2)) + 1 / 2ln 2\
&=quad ln(-1+sqrt(3))+ln(1+sqrt(2))-1 / 2ln 2
$
Expand Down Expand Up @@ -693,7 +693,7 @@ $
$
&quad integral.double_D x^2 / y^2 dif x dif y\
&= integral_1^2dif x integral_(1 / x)^x x^2 / y^2 dif y\
&= integral_1^2 (-x^2 / y)|_(y=1 / x)^(y=x) dif x\
&= integral_1^2 [-x^2 / y]_(y=1 / x)^(y=x) dif x\
&= integral_1^2 (-x+x^3) dif x\
&= -2^2 / 2 + 2^4 / 4 + 1 / 2 - 1 / 4\
&= 9 / 4
Expand Down Expand Up @@ -800,7 +800,7 @@ $
&=integral_0^(arctan R) dif theta integral_0^R sec^2 theta dot r dif r\
// &=integral_0^(arctan R) dif theta sec^2 theta r^2/2 |_0^R\
&=R^2/2 integral_0^(arctan R) sec^2 theta dif theta\
&=R^2/2 tan theta |_0^(arctan R)\
&=R^2/2 [tan theta]_0^(arctan R)\
// &=1/2 R^2 tan(arctan R)\
&=1/2 R^3
$
Expand Down

0 comments on commit 0ee593d

Please sign in to comment.