Integration Help ! (1 Viewer)

[Nah_f_u_studies]

Hi Guys ,

The question is:

Integrate 3/x

and the marking notes said that you need to use log function.

It may b easy bt i need help plz !

Thnx

 

[SpiralFlex]

To make it easy, take the constant out,

 

[Nah_f_u_studies]

Howd you do that ?

I kinda suck at log functions ... lol

 

[_deloso]

Howd you do that ?

I kinda suck at log functions ... lol

The derivative of a log function is log(x)= f(x)/ f'(x) so in your case, you would do the opposite. But the derivative of x isn't 3... however 3 is a constant therefore you can "take it out" of the function like the post above. Thus 3/x can also become 3 times 1/x. Now the derivative of x is 1. Therefore the integral of 1/x is a log function.. so log(x) but the three is still there. you would include that in the answer to become 3log(x)... oh and dont forget the constant. so 3log(x) + c

 

[SpiralFlex]

Howd you do that ?

I kinda suck at log functions ... lol

The definition of a logarithmic integral,

[Assuming ]

Now,





So hence if we integrate,



I put the absolute brackets since the logarithm is only defined for anything above 0.

With your form,



Since the top is the derivative of the bottom, which is -



We can integrate directly,

 

[Nah_f_u_studies]

The derivative of a log function is log(x)= f(x)/ f'(x) so in your case, you would do the opposite. But the derivative of x isn't 3... however 3 is a constant therefore you can "take it out" of the function like the post above. Thus 3/x can also become 3 times 1/x. Now the derivative of x is 1. Therefore the integral of 1/x is a log function.. so log(x) but the three is still there. you would include that in the answer to become 3log(x)... oh and dont forget the constant. so 3log(x) + c

Thank You !!

 

[SpiralFlex]

The derivative of a log function is log(x)= f(x)/ f'(x) so in your case, you would do the opposite. But the derivative of x isn't 3... however 3 is a constant therefore you can "take it out" of the function like the post above. Thus 3/x can also become 3 times 1/x. Now the derivative of x is 1. Therefore the integral of 1/x is a log function.. so log(x) but the three is still there. you would include that in the answer to become 3log(x)... oh and dont forget the constant. so 3log(x) + c

Other way. HSC stress?

 

[_deloso]

Other way. HSC stress?

lol yup my bad. give me a break. got physics tomorrow

 

[SpiralFlex]

lol yup my bad. give me a break. got physics tomorrow

I shall get some motors for you to study!