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:
m = 7
m = -7
Step-by-step explanation:
To find if a series is either geometric or arithmetic:
it must satisfy this property:
Arithmetic:
a(n+1) - a(n) = const
Geometric:
a(n+1)/a(n) = const
In your case:
r1 = 7 -4 = 3
r2 = 12 - 7 = 5
r1 != r2 (not arirthmetic)
Geometric check:
r1 = 7/4
r2 = 12/7
r1 != r2 (not Geometric)
so neither.
Answer:
<h2>-5</h2>
Step-by-step explanation:
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