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
Division CANNOT be commutative, here is why
lets say the problem is 24÷4
it is obviously 6
but when you flip 24÷4, you get 4÷24
and... 4÷24 is 0.16666666
6 and 0.1666 is totally different :p
M = -6/4
b = 7
equation : y = -6/4x+7
Given :
Ruth wants to buy a skateboard for $44.
She has $100 in her account. She spent $11.36 to buy stationary.
She also wants to buy some comic books for $3.72 each.
To Find :
The maximum number of comic books, n, that Ruth can buy so that she has enough money left to buy the skateboard.
Solution :
Money left after buying skateboard and stationary is :
Money left = $(100 - 11.36 - 44)
Money left = $44.64
Number of comic she can buy is :

Therefore, she can buy a maximum of 12 books.
Hence, this is the required solution.