Here are the solutions for problems 47, 48, 49, 50, and 52.
47. f(x)=5
- Step 1: Find f(a)
f(a)=5
- Step 2: Find f(a+h)
f(a+h)=5
- Step 3: Find the difference quotient
hf(a+h)−f(a)=h5−5=h0=*0*
48. f(x)=x+11
- Step 1: Find f(a)
f(a)=a+11
- Step 2: Find f(a+h)
f(a+h)=(a+h)+11
- Step 3: Find the difference quotient
hf(a+h)−f(a)=h(a+h)+11−a+11
Combine the fractions in the numerator:
=h((a+h)+1)(a+1)(a+1)−((a+h)+1)
=h((a+h)+1)(a+1)a+1−a−h−1
=h((a+h)+1)(a+1)−h
=h((a+h)+1)(a+1)−h
Cancel h:
= \text{*\frac{-1}{(a+h+1)(a+1)}*}
49. f(x)=x+1x
- Step 1: Find f(a)
f(a)=a+1a
- Step 2: Find f(a+h)
f(a+h)=(a+h)+1a+h
- Step 3: Find the difference quotient
hf(a+h)−f(a)=h(a+h)+1a+h−a+1a
Combine the fractions in the numerator:
=h((a+h)+1)(a+1)(a+h)(a+1)−a((a+h)+1)
Expand the numerator:
(a+h)(a+1)−a(a+h+1)=(a2+a+ah+h)−(a2+ah+a)
=a2+a+ah+h−a2−ah−a=h
Substitute back into the expression:
=h((a+h)+1)(a+1)h
=h((a+h)+1)(a+1)h
Cancel h:
= \text{*\frac{1}{(a+h+1)(a+1)}*}
50. f(x)=xx−1
- Step 1: Find f(a)
f(a)=aa−1
- Step 2: Find f(a+h)
f(a+h)=a+h(a+h)−1
- Step 3: Find the difference quotient
hf(a+h)−f(a)=ha+ha+h−1−aa−1
Combine the fractions in the numerator:
=ha(a+h)a(a+h−1)−(a−1)(a+h)
Expand the numerator:
a(a+h−1)−(a−1)(a+h)=(a2+ah−a)−(a2+ah−a−h)
=a2+ah−a−a2−ah+a+h=h
Substitute back into the expression:
=ha(a+h)h
=ha(a+h)h
Cancel h:
= \text{*\frac{1}{a(a+h)}*}
52. f(x)=x3
- Step 1: Find f(a)
f(a)=a3
- Step 2: Find f(a+h)
f(a+h)=(a+h)3
Expand (a+h)3:
f(a+h)=a3+3a2h+3ah2+h3
- Step 3: Find the difference quotient
hf(a+h)−f(a)=h(a3+3a2h+3ah2+h3)−a3
=h3a2h+3ah2+h3
Factor out h from the numerator:
=hh(3a2+3ah+h2)
Cancel h:
= \text{*3a^2 + 3ah + h^2*}