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
Answer:
Marta
Step-by-step explanation:
We are given that

We have to find who is correct and explain.
We know that
Equation: It is mathematical sentence that combines numbers and variables which shows the equality of two expressions.
Example:

Expression: It is mathematical phrase that combines numbers and variables
using mathematical operators.It can be evaluated but not solved.
Example:

By definitions

It is in equation form.
Therefore, Marta is correct.
Answer:
Look
Step-by-step explanation:
best solution is ask ur mom
She... she read 1/2 of a page in 1 minute...
Answer:
12) 5.96 ; 13)
Step-by-step explanation:
12). x and 5 are legs, so
opposite leg/adjacent leg = tangent 40°
5/x= tan40°, 5= x*tan40°, x= 5/tan40° ≈ 5.96
13). 15 is opposite leg
24 is hypotenuse
opposite leg/hypotenuse = sin(x)
sin(x) = 15/24
x = arcsin(15/24) ≈ 38.68°