Recent content by qq545282501

Homework Statement \int xydx+ 4ydy where C is the curve from (1,2) to (3,5) made up of the twoline segments parallel to the coordinate axes. c_1:(1,2)\rightarrow(3,2) c_2:(3,2)\rightarrow(3,5) Homework EquationsThe Attempt at a Solution i got c2 correct, y=2+3t, and x = 0, for t goes from 0...

oh interesting, I understand now. in order for z to be positive, y must be positive, which means first quadrant only. thx a lot !

no more classes left for this course though :( anyway,I just realized that if its 0 to pi, the volume become 0

thank you ! Oh i see why its 0 to pi, i just graphed that curve, i see its not centered at (0,0), its in the first and fourth quadrant. so i must have made a mistake when I took my notes in the class then?

Homework Statement use cylindrical coordinates to find the volume of the solid which is under z=xy, above xy-plane and inside the cylinder x^2+y^2=2x Homework EquationsThe Attempt at a Solution \int_{0}^{pi/2} \int_{0}^{2cos\theta} \int_{0}^{r^2\cos\theta\sin\theta} r\, dz \, dr \, d\theta...

so my approach was correct? thank you

Homework Statement A bird flew along a helical path r(t)=<5cost,5sint,2t>, at time t=10 second, the bird died instantly. where did it hit the xy-plane ? g=32 ft/s/s. Homework Equations r(t)=(v_0 \cos\theta t) i+(v_0 \sin\theta t - 0.5gt^2 + h_0) j The Attempt at a Solution taking derivative...

opps, got it. thank you

Homework Statement find all critical points and identify the locations of local maximums, minimums and saddle points of the function f(x,y)=4xy-\frac{x^4}{2}-y^2 Homework EquationsThe Attempt at a Solution setting Partial derivative respect to x = 0 : 4y-\frac{4x^3}{2}=0 setting partial...

gotcha, thank you

got it. thank you all.

Homework Statement use a double integral to find the volume bounded by the paraboloid :z=4-x^2-y^2, xy-plane and inside a cylinder: x^2+y^2=1 Homework Equations x=rcosθ y=rsinθ The Attempt at a Solution the radius of the area of integration is 1, since its determined by the cylinder only...

Homework Statement use triple integral to find volume of the solid in the first octant that is bounded above by x+2y+3z=6 and laterally by the clyinder x^2+y^2=4 Homework EquationsThe Attempt at a Solution From the given plane I got: Z=2-\frac{1} {3}x-\frac{2} {3}y from the given Cylinder i...

Ok, thank you, will do. but was my handwriting that bad :frown:

Homework Statement use spherical coordinates to find volume inside a sphere of radius 4 and outside sphere of radius 2, and inside/above the cone z=3√(x^2+y^2). Homework Equations [/B] x=rcosθ =ρsinφcosθ , y=rsinθ =ρsinφsinθ z=ρcosφ r= ρsinφ The Attempt at a Solution replacing z^2 in the...