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215pi/6 or 112.6 units2

Nope, no matter how many times I go through this question I just can't seem to get the right answer. I don't suppose anyone could show me their working?

Ah... My problem was that I was expanding the brackets before trying to find x2. Thanks.

Yeah, I agree. It's probably not worth it. Anyways, time for another question; Find the volume of the solid formed when the curve y = (x + 5)2 is rotated about the y-axis from y = 1 to y = 4. My main problem is figuring out exactly what x2 is equal to.

Thanks, you too. :)

Damnit! I keep thinking questions are more complicated than they really are, and keep forgetting my basics. Thanks.

*sigh* Another one; Evaluate pi/12∫pi/8 sec22x dx, in exact form. My working; [tan 2x]pi/12pi/8 [tan 2(pi/8)] - [tan 2(pi/12)] [tan pi/4] - [tan pi/6] [1/√2] - [1/√3] The answer is apparently (3 - √3)/6. Where am I going wrong?

The answer is apparently (17√17)/6, I'll check if it's the same. EDIT: Not quite. Anyways, I'm just gonna skip that question because it's kind of pointless; I'm not going to learn anything from it.

Yep. Thanks.

I forgot to mention, the question requires that you use 5 intervals. Sorry, that was probably the most important part and I left it out. :rolleyes:

I'm still having trouble with the last question I asked. Could someone please help me out here?

Here we go again; Find the exact area bounded by the parabola y = x2 and the line y = 4 - x. It's not so much that I don't know how to tackle this kind of question, it's more that I've made a mistake somewhere in the mass of equations that results, and I'm not sure where. Although, to be...

D'oh... That was stupid of me. I really have to concentrate more. :o EDIT: Ah, I see what my problem was with the second question now. Thanks.

Two questions this time. The first one is; Find the exact volume of the solid formed by rotating the curve y = 1/x about the x-axis between x = 1 and x = 3. The answer should be 2pi/3, but I end up with -2pi/3. The second question is; Find the total area enclosed between the curve y = x(x -...

So I did. Thanks.

Question time again; Find the area enclosed between the curve y = 3/(x - 2), the y-axis and the lines y = 1 and y = 3 My working; y = 3/(x - 2) y(x - 2) = 3 x - 2 = 3/y x = 3/y + 2 x = 3y-1 + 2 1∫3 3y-1 + 2 dy [3 + 2y]13 [3 + 2(3)] - [3 + 2(1)] [9] - [5] 4 However, the answer should be...

No, you're right. Thanks. :) EDIT: Ugh... I see my mistake now. Stupid error, for some reason (in the second question) I made one of the integrals 16/6 instead of 17/7...

Man, I should have seen that myself. For some reason I didn't make the connection between using the first part of the question in the solution to the second... :o

More maths trouble, this time with polynomials; A polynomial P(x) = (x - b)7 Q(x) a) Show that P(b) = P'(b) = 0 This first part is pretty easy, but it's the second part I'm not sure about... b) Hence find a and b if (x - 1)7 is a factor of x7 + 3x6 + ax5 + x4 + 3x3 + bx2 - x - 1 Who can...

I'm having some trouble with this question, and I'm not sure if it's because the textbook has the wrong answer or if it's because I'm going completely off the track with my working. Could someone walk me through the problem, so I can see if and/or where I'm making a mistake? Here's the question...