Answer:
First one.
Step-by-step explanation:
0.3/3=0.1 ==> 0.1$ per meter
0.77/7 ==> 0.11$ per meter
The first option is cheaper, therefore better to buy if you agree with "the cheaper. the better".
Step-by-step explanation:
Find the difference
3,621 - 1,836 = 1,785
They payed $1,785 dollars in the second installment.
Answer:
•cos(s+t) = cos(s)cos(t) - sin(s)sin(t) = (-⅖).(-⅗) - (√21 /5).(⅘) = +6/25 - 4√21 /25 = (6-4√21)/25
•cos(s-t) = cos(s)cos(t) + sin(s)sin(t) = (-⅖).(-⅗) + (√21 /5).(⅘) = +6/25 + 4√21 /25 = (6+4√21)/25
cos(t) = ±√(1 - sin²(t)) → -√(1 - sin²(t)) = -√(1 - (⅘)²) = -⅗
sin(s) = ±√(1 - cos²(s)) → +√(1- cos²(s)) = +√(1 - (-⅖)²) = √21 /5
