Recent content by xllx

Homework Statement A circle has the parametric equations: x=1+2cos\theta y=3+2sin\theta dy/dx= -1/tan\theta Find the tangent equation at the point with parameter \theta Homework Equations y-y1=m(x-x1) The Attempt at a Solution I've tried putting dy/dx in as the gradient and...

Homework Statement A horizontal piece of wood that has a weight 40N is held in equilibrium by two brackets, A and B. The wood is 1.6m long (CD). A is 0.4m from C and B is 0.2m from D. Meaning that there is 1.0m between A and B. At rest the reaction force at A is 24 N and at B 16N. When an...

Homework Statement A plank of wood is lifted off the ground so it has one side on the ground (A) and the rest of the wood at a slope at 15degrees to the horizontal. The length of the wood (AC) is 2.5m. A force is applied at C at 65degrees to the horizontal to the left keeping it in...

Thankyou. Redid it and came out with a reasonal answer.

Homework Statement Using integration by parts, integrate: (1/x^2)(lnx) dx with the limits e and 1 Homework Equations [uv]to the limits a b - the integral of (v)(du/dx) dx (sorry, don't know how to write out equations properly on a computer) The Attempt at a Solution I've...

Does lne=1?? But I don't know how that solves this, does that mean x=e?

Yes sorry just realized that.. I redid it and got dy/dx=1-lnx/(x^2lnx^2), which sounds a more accurate answer and think I have done it right this time. Is is possible to just extend this question though: If I was to find when the gradient equals 0, I've got 0=1-lnx so 1=lnx, but how would I...

Homework Statement Find dy/dx of y=1/xlnx Homework Equations I thought that I'd have to use the quotient rule: y'=vu'-uv'/v^2 However the differential of 1 is 0, so is this the right rule to use? The Attempt at a Solution u=1 u'=0 v=xlnx v'=1/x y'=vu'-uv'/v^2...

Thankyou!

Is it zero?

Well wouldn't x be infinity in that case? But this question is referring to co-ordinates of a turning point so surely a turning point can't be infinity? The original equation was y=(x^2)(e^-x) Which I differentiated into: dy/dx=x^2(-e^-x)+(e^-x)2x Which I factorised into...

Homework Statement 0=x(e^-x) Homework Equations The Attempt at a Solution Well as x is a multiple that leaves: 0=e^-x so does x=0? Any help at all would be greatly appreciated. Many Thanks.

Sorry I think I've got slightly confused with the letters. I think that it is 90-a because the angles are along a straight line and so will add up to 180 degrees. And so the angle between string B and C is 90 degrees so angle (a) plus the angle between A and the line has also got to add up to 90...

So the perpendicular equations will equal the reaction force (R), totally forgot about that. Thanks. Oh and will the 5kg truck also have the Tension from the coupling and tension from the string? So it will be: 5gsin10+8-T2=T1 From there will I have to do simultaneous equations? But...

Homework Statement An object has a weight of 20N. It is supported by three strings to keep it in equilibrium, all attached to a smooth ring on the object. String A has a tension of 15N to the right of the block. String B is (a)degrees away from string A and String C is 90degrees away from...