Let’s solve the two problems from the uploaded image.
1. Find ∫xx+5x2+3dx:
We begin by rewriting the integral:
∫xx+5x2+3dx=∫xxdx+∫x5x2dx+∫x3dx
Each term is simplified using the property xmxn=xn−m:
xx=x1−21=x21,x5x2=5x2−21=5x23,x3=3x−21
So the integral becomes:
∫x21dx+∫5x23dx+∫3x−21dx
Now we integrate each term using the power rule for integration ∫xndx=n+1xn+1+C (where n=−1):
- ∫x21dx=21+1x21+1=23x23=32x23
- ∫5x23dx=5⋅23+1x23+1=5⋅25x25=5⋅52x25=2x25
- ∫3x−21dx=3⋅−21+1x−21+1=3⋅21x21=3⋅2x21=6x21
Adding them together, the result is:
∫xx+5x2+3dx=32x23+2x25+6x21+C
2. Find dx3d3y if y=2sin(2x)+cos(x):
Step 1: First derivative (y′):
y=2sin(2x)+cos(x)
The derivatives of sin(2x) and cos(x) are:
- dxd[sin(2x)]=2cos(2x) (by the chain rule),
- dxd[cos(x)]=−sin(x).
So:
y′=dxd[2sin(2x)+cos(x)]=2⋅2cos(2x)−sin(x)=4cos(2x)−sin(x)
Step 2: Second derivative (y′′):
y′=4cos(2x)−sin(x)
Now differentiate term by term:
- dxd[4cos(2x)]=4⋅(−2sin(2x))=−8sin(2x),
- dxd[−sin(x)]=−cos(x).
So:
y′′=−8sin(2x)−cos(x)
Step 3: Third derivative (y′′′):
y′′=−8sin(2x)−cos(x)
Now differentiate again:
- dxd[−8sin(2x)]=−8⋅2cos(2x)=−16cos(2x),
- dxd[−cos(x)]=sin(x).
So:
y′′′=−16cos(2x)+sin(x)
Final Answers:
- ∫xx+5x2+3dx=32x23+2x25+6x21+C
- dx3d3y=−16cos(2x)+sin(x)
Do you want further clarification or more details?
Here are 5 related questions for further exploration:
- How would you evaluate definite integrals for similar functions, such as ∫14xx+5x2+3dx?
- What is the importance of the chain rule in differentiation, as seen in the second problem?
- How does the power rule for integration extend to functions with fractional exponents?
- Can you explain how to verify the result of a third derivative using numerical methods?
- How would the integral change if the numerator had higher powers of x, such as x3?
Tip: Always rewrite integrals in terms of simpler powers before solving—it makes applying the power rule much easier!