Answer:
(e) csc x − cot x − ln(1 + cos x) + C
(c) 0
Step-by-step explanation:
(e) ∫ (1 + sin x) / (1 + cos x) dx
Split the integral.
∫ 1 / (1 + cos x) dx + ∫ sin x / (1 + cos x) dx
Multiply top and bottom of first integral by the conjugate, 1 − cos x.
∫ (1 − cos x) / (1 − cos²x) dx + ∫ sin x / (1 + cos x) dx
Pythagorean identity.
∫ (1 − cos x) / (sin²x) dx + ∫ sin x / (1 + cos x) dx
Divide.
∫ (csc²x − cot x csc x) dx + ∫ sin x / (1 + cos x) dx
Integrate.
csc x − cot x − ln(1 + cos x) + C
(c) ∫₋₇⁷ erf(x) dx
= ∫₋₇⁰ erf(x) dx + ∫₀⁷ erf(x) dx
The error function is odd (erf(-x) = -erf(x)), so:
= -∫₀⁷ erf(x) dx + ∫₀⁷ erf(x) dx
= 0
Answer:
9.9 years
Step-by-step explanation:
A = P e ^(rt)
Where A is the amount in the account
P is the amount invested
R is the interest rate
t is the time
P = 8500
r =7% = .07
A = 17000
Substituting into the equation
17000=8500 e^(.07t)
Divide each side by 8500
17000/8500=8500/8500 e^(.07t)
2 = e^(.07t)
Take the natural log of each side
ln (2) = ln e^(.07t)
ln(2) = .07t
Divide each side by .07
ln(2)/.07 = .07t/.07
ln(2)/.07 = t
9.902102579=t
Rounding to one decimal place
9.9 years
Please try to follow this closely.
Ready ? OK, here goes:
<em> Add 2.6 to each side of the equation.</em>
