s10 = -20
n = 10
an = -20
solution
s10 = n\2 [a+(n-1)d]
-20 = 10a2[a+(10-1)4]
-4 = a +36
a1 = -40
Hope it helps.
Hope it helps
Answer:
Step-by-step explanation:
The mnemonic SOH CAH TOA reminds you of the relation between the cosine of an angle and the sides of the triangle.
Cos = Adjacent/Hypotenuse
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<h3>Angle A</h3>In the given triangle, the hypotenuse is AC. The side adjacent to angle A is AB, so its cosine is ...
cos(A) = AB/AC
cos(A) = 3/5
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<h3>Angle B</h3>The right angle in the triangle is angle B. The cosine of a right angle is 0.
cos(B) = 0
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<h3>Angle C</h3>The side adjacent to angle C is CB, so its cosine is ...
cos(C) = CB/AC
cos(C) = 4/5
