Here are the solutions to the problems.
:
If 3x2−5y3+xy−1=0, find dxdy at the point (5,−2).
Step 1: Differentiate the equation implicitly with respect to x. Remember to use the chain rule for terms involving y and the product rule for xy.
dxd(3x2)−dxd(5y3)+dxd(xy)−dxd(1)=dxd(0)
6x−15y2dxdy+(1⋅y+x⋅dxdy)−0=0
6x−15y2dxdy+y+xdxdy=0
Step 2: Group terms containing dxdy and move other terms to the other side of the equation.
xdxdy−15y2dxdy=−6x−y
Step 3: Factor out dxdy and solve for it.
dxdy(x−15y2)=−6x−y
dxdy=x−15y2−6x−y
Step 4: Substitute the given point (x,y)=(5,−2) into the expression for dxdy.
dxdy=5−15(−2)2−6(5)−(−2)
dxdy=5−15(4)−30+2
dxdy=5−60−28
dxdy=−55−28
dxdy=5528
The value of dxdy at the point (5,−2) is 5528.
:
Given that A=(x2133x) and B=(326x), find the possible values of x such that AB=BA.
Step 1: Calculate the product AB.
AB=(x2133x)(326x)
AB=((x2)(3)+(3)(2)(1)(3)+(3x)(2)(x2)(6)+(3)(x)(1)(6)+(3x)(x))
AB=(3x2+63+6x6x2+3x6+3x2)
Step 2: Calculate the product BA.
BA=(326x)(x2133x)
BA=((3)(x2)+(6)(1)(2)(x2)+(x)(1)(3)(3)+(6)(3x)(2)(3)+(x)(3x))
BA=(3x2+62x2+x9+18x6+3x2)
Step 3: Set AB=BA and equate the corresponding elements.
(3x2+63+6x6x2+3x6+3x2)=(3x2+62x2+x9+18x6+3x2)
Equating the (1,2) elements:
6x2+3x=9+18x
6x2−15x−9=0
Dividing by 3:
2x2−5x−3=0
Equating the (2,1) elements:
3+6x=2x2+x
0=2x2+x−6x−3
2x2−5x−3=0
Both equations lead to the same quadratic equation.
Step 4: Solve the quadratic equation 2x2−5x−3=0.
We can factor the quadratic equation:
(2x+1)(x−3)=0
This gives two possible values for x:
2x+1=0⟹2x=−1⟹x=−21
x−3=0⟹x=3
The possible values of x are −21,3.
3 done, 2 left today. You're making progress.