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# mathematics watch

1. 2a
∫ (10-6x)dx=1
a

find the two posible vales of a?

can someone plz help me with this. we haven't even done these in class and my teacher expects us to do it for homework...
2. (Original post by hancyk)
2a
∫ (10-6x)dx=1
a

find the two posible vales of a?

can someone plz help me with this. we haven't even done these in class and my teacher expects us to do it for homework...
Do you know how to integrate 10-6x without the limits?
3. (Original post by Matrix123)
Do you know how to integrate 10-6x without the limits?
yes but what do i do after that
4. (Original post by hancyk)
yes but what do i do after that
After that you have to write integrated answer in square brackets with the limits written at the top bottom and right hand side.
You substitute your upper limit into the answer then substitute the lower limit into it. Then you subtract the latter from the former.
As you know this is equal to 1, you can equate this to 1 and solve for a
5. (Original post by hancyk)
yes but what do i do after that
You substitute the limits as you normally would and then solve for a. For example:

a
∫ (x) dx=1 ---> [(x^2)/2] (with limits a and 0) = (a^2)/2 - (0^2)/2 = (a^2)/2 = 1 ---> a = 2^(1/2)
0
6. (Original post by hancyk)
yes but what do i do after that
Keep finding the definite integral as you would normally, but using a instead of numerical values. If you equate that to 1, then you should be able to form a quadratic in a.
7. hancyk
http://www.bbc.co.uk/bitesize/higher...on/revision/2/
This should help if my post didn't
8. (Original post by ineedhelppls123)
You substitute the limits as you normally would and then solve for a. For example:

a
∫ (x) dx=1 ---> [(x^2)/2] (with limits a and 0) = (a^2)/2 - (0^2)/2 = (a^2)/2 = 1 ---> a = 2^(1/2)
0

(Original post by Matrix123)
After that you have to write integrated answer in square brackets with the limits written at the top bottom and right hand side.
You substitute your upper limit into the answer then substitute the lower limit into it. Then you subtract the latter from the former.
As you know this is equal to 1, you can equate this to 1 and solve for a
thank you
9. (Original post by hancyk)
2a
∫ (10-6x)dx=1
a

find the two posible vales of a?

can someone plz help me with this. we haven't even done these in class and my teacher expects us to do it for homework...
10x-3x^2 then sub in 2a and a, take them away, rearrange and solve for a.

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