Answer:
1) ∫ x² e^(x) dx
4) ∫ x cos(x) dx
Step-by-step explanation:
To solve this problem, eliminate the choices that can be solved by substitution.
In the second problem, we can say u = x², and du = 2x dx.
∫ x cos(x²) dx = ∫ ½ cos(u) du
In the third problem, we can say u = x², and du = 2x dx.
∫ x e^(x²) dx = ∫ ½ e^(u) du
Answer:
Sister = 15 years old
Brother = 12 years old
Step-by-step explanation:
Right now, if the brother is B years old and the sister is S years old, B = (4/5)S because the ratio from brother to sister is 4:5, so if one unit is X, B = 4X and S = 5X
Three years ago, the brother was B-3 years old and the sister was S-3 years old. Keeping one unit as X, we have
B = 3X
S = 4X
B-3 = (3/4)(S-3)
Therefore, we have a system of equations
B = (4/5)S
B-3 = (3/4)(S-3)
Substitute (4/5)S for B into the second equation to only have one variable
(4/5)S - 3 = (3/4)(S-3)
(4/5)S - 3 = (3/4)S - 9/4
add 3 to both sides and subtract (3/4)S from both sides to isolate the variable and its coefficient
(1/20)S = 3/4
multiply both sides by 20 to isolate the S
S = 15
B = (4/5)S = 12
Answer:
$68 to hire and 28.25 per hour to hire both
Step-by-step explanation:
Beach invasions beach invasions
