Integration question (1 Viewer)

[highkeydropout]

Hi, does anyone know how to solve:

 

[qUiCkMaThS]

Is the answer 21?

 

[highkeydropout]

15

Is the answer 21?

 

[highkeydropout]

Is the answer 21?

i got 21 aswell, but I thought we subtract the bottom two from the area of the top? not sure tho

 

[qUiCkMaThS]

well, idk what I've done wrong, but if you find it, just point it out:

A1 + A2 + A3 = ATotal
A2 + A3 = 5A1/ 2

Since A1 = 3 x 2 = 6

ATotal = 15+6 = 21

i got 21 aswell, but I thought we subtract the bottom two from the area of the top? not sure tho

I've forgotten whether 'evaluate' changes what the question is asking....sorry about that!

 

[highkeydropout]

well, idk what I've done wrong, but if you find it, just point it out:

A1 + A2 + A3 = ATotal
A2 + A3 = 5A1/ 2

Since A1 = 3 x 2 = 6

ATotal = 15+6 = 21



I've forgotten whether 'evaluate' changes what the question is asking....sorry about that!

no problem!! that's exactly what I got, it may be an error in the question, thank you!!

 

[B1andB2]

no the answer seems right

-15?

 

[B1andB2]

A1=6
A2= 3
A3 = 5(3x2)-2(3)/2 = 12

when you evaluate the integral (not the same as finding area) you consider the fact that below= negative

so solving the integral = -6+3-12 = -15

 

[highkeydropout]

A1=6
A2= 3
A3 = 5(3x2)-2(3)/2 = 12

when you evaluate the integral (not the same as finding area) you consider the fact that below= negative

so solving the integral = -6+3-12 =15

yesss that makes sense, thank you tooo!!

 

[B1andB2]

15

are you sure it's 15?

it seems to be -15 the way im doing it

 

[highkeydropout]

are you sure it's 15?

it seems to be -15 the way im doing it

my mistake it is -ve, sorry!

 

[notme123]

are you sure it's 15?

it seems to be -15 the way im doing it

I think it's -21. A1 should be -6 I think, not +6.

 

[B1andB2]

I think it's -21. A1 should be -6 I think, not +6.

A1 means the area so it should be positive when you use it to find area 3

when you solve the integral though, you take the negative because it’s below

 

[notme123]

A1 means the area so it should be positive when you use it to find area 3

when you solve the integral though, you take the negative because it’s below

Oh ok with the equation they give you they mean areas so it's positive. Understood

 

[YonOra]

A1=6
A2= 3
A3 = 5(3x2)-2(3)/2 = 12

when you evaluate the integral (not the same as finding area) you consider the fact that below= negative

so solving the integral = -6+3-12 = -15

How'd u get A2 to be 3. Having an elderly moment

 

[B1andB2]

How'd u get A2 to be 3. Having an elderly moment

area of a triangle is half breadth times height

 

[YonOra]

No i was about to delete it. I thought A3 was A2 and i was like what

 

[YonOra]

Year 7 maths coming to bite me