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Zinaida [17]
3 years ago
13

Can someone plz help

Mathematics
1 answer:
omeli [17]3 years ago
6 0
i) 1/2
ii) if by between 13 and 19 it means 14,15,16,17, and 18 it is 5/12
iii) 3/12
iv) 0/12
V) 3/12
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Prove that sin3a-cos3a/sina+cosa=2sin2a-1
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Answer:

\frac{sin(3a)-cos(3a)}{sin(a)+cos(a)} =2sin(2a)-1

Step-by-step explanation:

we are given

\frac{sin(3a)-cos(3a)}{sin(a)+cos(a)} =2sin(2a)-1

we can simplify left side and make it equal to right side

we can use trig identity

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\frac{(3sin(a)-4sin^3(a))-(4cos^3(a)-3cos(a))}{sin(a)+cos(a)}

now, we can simplify

\frac{3sin(a)-4sin^3(a)-4cos^3(a)+3cos(a)}{sin(a)+cos(a)}

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now, we can factor it

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2sin(a)cos(a)=sin(2a)

we can replace it

=2sin(2a)-1

so,

\frac{sin(3a)-cos(3a)}{sin(a)+cos(a)} =2sin(2a)-1


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