Hey Jordan, good to see you again.
Let's solve Question 1 and Question 2.
Question 1: Differentiate the following equations
a) y=x2lnx
Step 1: Apply the quotient rule dxd(vu)=v2u′v−uv′.
Let u=lnx⟹u′=x1.
Let v=x2⟹v′=2x.
dxdy=(x2)2(x1)(x2)−(lnx)(2x)
Step 2: Simplify the expression.
dxdy=x4x−2xlnx
dxdy=x4x(1−2lnx)
\frac{dy}{dx} = *\frac{1 - 2 \ln x{x^3}*}
b) y=(x3+3x)5
Step 1: Apply the chain rule dxd(f(g(x)))=f′(g(x))g′(x).
Let g(x)=x3+3x, so g′(x)=3x2+3.
Let f(u)=u5, so f′(u)=5u4.
dxdy=5(x3+3x)4⋅(3x2+3)
Step 2: Factor out common terms.
dxdy=5(x3+3x)4⋅3(x2+1)
dxdy=∗15(x3+3x)4(x2+1)∗
c) y=e2xsinx
Step 1: Apply the product rule dxd(uv)=u′v+uv′.
Let u=e2x⟹u′=2e2x.
Let v=sinx⟹v′=cosx.
dxdy=(2e2x)(sinx)+(e2x)(cosx)
Step 2: Factor out the common term e2x.
dxdy=∗e2x(2sinx+cosx)∗
d) y=2x4−5x2+6x+1
Step 1: Differentiate each term using the power rule.
dxdy=dxd(2x4)−dxd(5x2)+dxd(6x)+dxd(1)
dxdy=2(4x3)−5(2x1)+6(1)+0
dxdy=∗8x3−10x+6∗
Question 2: Two sequences Un=2n+1 and Vn=Un2−3 for n≥1.
I. Write down the first four terms of the sequence (Un).
Step 1: Substitute n=1,2,3,4 into Un=2n+1.
For n=1:U1=2(1)+1=3
For n=2:U2=2(2)+1=5
For n=3:U3=2(3)+1=7
For n=4:U4=2(4)+1=9
The first four terms are ∗3,5,7,9∗.
II. Hence, write down the first four terms of the sequence (Vn).
Step 1: Substitute the terms of Un into Vn=Un2−3.
For n=1:V1=U12−3=32−3=9−3=6
For n=2:V2=U22−3=52−3=25−3=22
For n=3:V3=U32−3=72−3=49−3=46
For n=4:V4=U42−3=92−3=81−3=78
The first four terms are ∗6,22,46,78∗.
III. Show that Vn=4n2+4n−2.
Step 1: Substitute Un=2n+1 into the expression for Vn.
Vn=(2n+1)2−3
Step 2: Expand the squared term and simplify.
Vn=(4n2+4n+1)−3
Vn=∗4n2+4n−2∗
IV. Determine whether the sequence Un and Vn is a GP or AP.
Step 1: Check Un for AP and GP.
The terms of Un are 3,5,7,9,…
Common difference: U2−U1=5−3=2. U3−U2=7−5=2.
Since there is a constant common difference, Un is an Arithmetic Progression (AP).
Common ratio: U1U2=35. U2U3=57. Since the ratios are not equal, Un is not a GP.
Step 2: Check Vn for AP and GP.
The terms of Vn are 6,22,46,78,…
Common difference: V2−V1=22−6=16. $V_3