WorksheetsFunctions of several variable
Total questions: 10
Worksheet time: 5mins
If x2+y2=25 , then dxdy=
-x/y
y/x
-y/x
x/y
The Taylors expansion of first order of f(x)=excosy about (0,0) is
1+x
1+x−y
1+x−(2y2)
1+x−ysin(0)
For f(x,y)=x2−y2 , the point (0,0) is
Maximum
Minimum
Saddle point
undeterminable
Maximize f(x,y,z)=xyz subject to x+y+z=6 . The maximum value occurs at
(1,2,3)
(2,2,2)
(3,2,1)
(0,3,3)
If x=rcosϕ, y=rsinϕ , then J(r,ϕx,y) is
r2
0
r
-r
If two functions are dependent, then their Jacobian is
Positive
Negative
Zero
Infinity
The method of Lagrange multipliers is used to
Approximate a function by series
Find maxima/minima subject to a constraint
Differentiate implicit functions
Transform coordinates
For a function f(x,y) , a point (x0,y0) is called a critical point if
f(x0,y0)=0
f(x0,y0) is maximum only
fx(x0,y0)=fy(x0,y0)=0
The point lies on the x- axis
The Taylor series expansion of a function of two variables f(x,y) about (a,b) is
Expansion in powers of x and y only
Expansion involving only linear terms
A polynomial approximation without derivatives
Expansion involving partial derivatives of f at (a,b)
The Jacobian of the inverse transformation satisfies the property
J(x,yu,v )×J(u,vx,y )=0
J(x,yu,v )=J(u,vx,y )
J(x,yu,v )=0
J(x,yu,v )×J(u,vx,y )=1
