What is the measure of AngleS to the nearest whole degree? 19° 26° 30° 33°
2 answers:
Answer:
A= 33 degrees
A=33°
Step-by-step explanation:
THIS IS THE COMPLETE QUESTION BELOW, ALSO CHECK THE ATTACHMENT FOR THE DIAGRAM
Law of cosines: a2 = b2 + c2 – 2bccos(A) What is the measure of S to the nearest whole degree? 19° 26° 30° 33°
EXPLANATION
Accordingto the law of cosines in
trigonometry, which gives the relationship between the lengths of the sides of a triangle to the cosine of one of its angles.
From the diagram at the attachment, the sides of the triangle are:a=10 ,b=17 ,c=18
The law can is described using the formula below;
a² = b²+ c² – 2*b*c*cos(A)
To get the angle cos(A), we make cos(A) subject of formula
cos(A)=[b²+c²-a²]/[2*b*c]
Then inserting the figures
cos (A)=[17²+18²-10²]/[2*17*18]
cos (A)=0.8382
Then find the inverse of cos(A)
A=arc cos (0.8382)
A=33.05°
A=33°( approximately)
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Answer:
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Step-by-step explanation:
We want to find the sum of the first 20 terms of the arithmetic sequence:
4, -4, -12, -20...
The sum of an arithmetic sequence is given by:
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Since we want to find the sum of the first 20 terms, <em>k</em> = 20.
Our initial term <em>a</em> is 4.
Our last term is also the 20th term as we want the sum of the first 20 terms.
To find the 20th term, we can write an explicit formula for our sequence. The explicit formula for an arithmetic sequence is given by:
Where <em>a</em> is the initial term, <em>d</em> is the common difference, and <em>n</em> is the <em>n</em>th term.
Our initial term is 4. From the sequence, we can see that our common difference is -8 since each subsequent term is eight less than the previous term. Therefore:
Then the last or 20th term is:
Therefore, the sum of the first 20 terms are: