integration (1 Viewer)

[dawso]

hey all, got these 2 questions, got an answer but its different to answer supplied, any one got any ideas?

1) The curved leg of a billiard table will be turned on a lathe using the equation y= sinx + 2 with x between 0 and 5pi/2. calculate the volume of the wood in 4 legs where 1 unit equals 10 cm

2) calculate the integral between 0 + 1 of (x . root(1+3x))dx, i think i descibed that right....

cheers guys

-dawso

 

[shafqat]

hey all, got these 2 questions, got an answer but its different to answer supplied, any one got any ideas?

1) The curved leg of a billiard table will be turned on a lathe using the equation y= sinx + 2 with x between 0 and 5pi/2. calculate the volume of the wood in 4 legs where 1 unit equals 10 cm

2) calculate the integral between 0 + 1 of (x . root(1+3x))dx, i think i descibed that right....

cheers guys

-dawso

for 2 i get 116/135

 

[dawso]

for 2 i get 116/135

ok, i have come to 2 conclusions,
1) that was dayem quick, and
2) the answer there is wrong

thats wat i got 2, cheers man

wat people getting for the first one?

 

[FinalFantasy]

116\135 for 2

 

[Trev]

1) The curved leg of a billiard table will be turned on a lathe using the equation y= sinx + 2 with x between 0 and 5pi/2. calculate the volume of the wood in 4 legs where 1 unit equals 10 cm

π int. (sinx + 2)²dx {from 5π/2 to 0}
π int. (sin²x + 4sinx + 4)dx {from 5π/2 to 0}
π/2 int. (1 - cos2x)dx + 4π int. (sinx + 1)dx {from 5π/2 to 0}
π/2[x - (sin2x)/2] + 4π[x - cosx] {from 5π/2 to 0}
(45π²)/4 + 4π; 1 unit = 1000cm².
= (45000π²)/4 + 4000π
= 123599cm³ to nearest cm³.

 

[shafqat]

1 unit = 10 cm
1 unit^3 = 1000 cm^3

 

[Trev]

1 unit = 10 cm
1 unit^3 = 1000 cm^3

Thanx, edited.

 

[dawso]

π int. (sinx + 2)²dx {from 5π/2 to 0}
π int. (sin²x + 4sinx + 4)dx {from 5π/2 to 0}
π/2 int. (1 - cos2x)dx + 4π int. (sinx + 1)dx {from 5π/2 to 0}
π/2[x - (sin2x)/2] + 4π[x - cosx] {from 5π/2 to 0}
(45π²)/4 + 4π; 1 unit = 1000cm².
= (45000π²)/4 + 4000π
= 123599cm³ to nearest cm³.

i get : π/2[x - (sin2x)/2] + 4π[x - cosx] {from 5π/2 to 0}

but then to the next line, i got no idea where ya comin from?? thanks trevy....