Recent content by erik05

Hello everybody, just wondering if anyone could point me in the right direction for this question. Please and thanks. 1) Since the ionisation process takes an electron from its ground state to the zero level of the energy scale, the ground state energy calculated for the electron of the...

I seem to be having trouble on this one integral.Any help would be much appreciated. \int 3x \sqrt{5-2x} dx I'm assuming the substitution rule applies to this so I have u=5-2x. Then du=-2dx And now I'm stuck. How can I get 3xdx to equal -2dx? Please and thanks.

I can't believe I didn't get that...thanks.

Stupid question...but why to the exponent of 3?

Hello all. Really quick question here...What are the intervals of increase and decrease for y= e^x = e^-2x. I found the first derivative : y'= e^x-2e^-2x and set it equal to 0 but that's where I got stuck. How would you solve for x? I know that the answer is (ln2)/3 but how would you get there...

I guess I'll just assume that the book is wrong.

That's what the answer in the back of the book says. It's weird because you'd think it would be in rad/s or degrees/s...

I get the same answer too except that it's negative, which makes sense since it's decreasing. This is what I did: sin\theta= \frac {40}{80} and taking the inverse of that I get 30 degrees. From before: \frac {dx}{dt}= -80sin\theta \frac {d\theta}{dt} \frac {d\theta}{dt}= \frac...

That's the thing, I never know what to start with so I really don't have that much work. I'm assuming that all of these questions are involving triangles and that the cosine law could come in handy for a few of them.

Hello all. I have a test on these type of questions coming up soon and this is about the time when frustration sets in since I'm not very good at these questions. If anyone could show me how to do them so I could study off it then you would be my hero. 1) A wall of height 8 m stands...

Ah...I got it. Thanks all.

That I do know.

This is going to sound really pathetic but no, we haven't the taylor series either.

Sorry, I haven't learned l'hospital's rule yet and we're not suppose to use it for these questions.

Hello all. I missed a class in calculus so I didn't get the notes on this so if anyone could explain this question for me, it would be much appreciated. \lim_{x \rightarrow 0} \frac {tanx}{4x} = \frac {sinx}{cos4x} ? Not really too sure if I manipulated the equation right. Any hints...