Using the standard integral formula ∫x2+a2dx=a1tan−1(ax)+c. Here a=2, so ∫x2+22dx=21tan−1(2x)+c.
12.The limit of the function f(x)=xex−1 as x→0 is:
a)
−1
b)
1
✓ Correct Answer
c)
0
d)
does not exist
💡 Complete Solution & Explanation:
Using L'Hôpital's rule for the indeterminate form 00: limx→0dxd(x)dxd(ex−1)=limx→01ex=e0=1.
13.The function f(x)=x3−2x is increasing at the interval:
a)
[0,∞)
b)
[2,∞)
c)
(0,∞)
d)
(1,∞)
✓ Correct Answer
💡 Complete Solution & Explanation:
Find f′(x)=3x2−2. For the function to be increasing, f′(x)>0⟹3x2>2⟹x2>32⟹x>32≈0.816. Among choices, (1,∞) fits the criteria.
14.The stationary points of y=x3−6x are:
a)
0,±6
✓ Correct Answer
b)
0,1
c)
0,±4
d)
±2
💡 Complete Solution & Explanation:
Set the first derivative to zero: y′=3x2−6=0. This gives x2=2, so x=±2. However, the stationary points are values where the slope is zero, hence 3x2−6=0⟹x=±2.
15.The area below the curve y=x3, x-axis and ordinates at x=0 and x=2 is:
16.The maximum value of Z=4x+y at (0,0),(30,0),(20,30) and (0,50) is:
a)
510
b)
120
✓ Correct Answer
c)
110
d)
50
💡 Complete Solution & Explanation:
Evaluate Z=4x+y at each point: Z(0,0)=0,Z(30,0)=4(30)+0=120,Z(20,30)=4(20)+30=110,Z(0,50)=4(0)+50=50. The maximum value is 120.
17.If the initial value to approximate the root of x−13=0 is 3.5, then the value of one iteration using Newton-Raphson method is:
a)
2.687
b)
2.678
✓ Correct Answer
c)
3.607
d)
3.597
💡 Complete Solution & Explanation:
Newton-Raphson formula: xn+1=xn−f′(xn)f(xn). Here f(x)=x−13, f′(x)=1. x1=3.5−13.5−13=3.5−(−9.5)=13. Correction: Given provided options, if x was meant as x2−13=0, then x1=3.5−2(3.5)3.52−13=3.5−712.25−13=3.5−7−0.75=3.5+0.107=3.607.
18.The solution of dxdy=e−x when y(0)=0 is:
a)
y=−e−x+1
✓ Correct Answer
b)
y=ex+c
c)
y=−ex+e−c
d)
y=ex
💡 Complete Solution & Explanation:
Integrating both sides: ∫dy=∫e−xdx⟹y=−e−x+c. Applying the condition y(0)=0: 0=−e0+c⟹c=1. Thus, y=−e−x+1.
19.What is the value of dxdy if x=et and y=2t?
a)
et1
b)
tet
c)
et2
✓ Correct Answer
d)
et
💡 Complete Solution & Explanation:
By chain rule, dxdy=dx/dtdy/dt. Here, dtdy=2 and dtdx=et. Therefore, dxdy=et2.
20.The differential equation dx2d2y=1+(dxdy)2 is of:
a)
Second degree, second order
b)
Second degree, first order
c)
First degree, second order
✓ Correct Answer
d)
First degree, first order
💡 Complete Solution & Explanation:
The order is the highest derivative present, which is 2. The degree is the power of the highest derivative when the equation is free from radicals. Squaring both sides gives (dx2d2y)2=1+(dxdy)2. The degree is 2.
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