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sierraurb
Group Title
PLEASE HELP!!
A rain gutter is to be constructed of aluminum sheets 12 inches wide. After marking off a length of 4 inches from each edge, this length is bent up at an angle Θ. The area A of the opening may be expressed as the function: A(Θ) = 16 sin Θ • (cos Θ + 1). If Θ = 90°, what is the area of the opening?
When i plug 90 in i keep getting 15, but my choices are:
21.8 in2
16.0 in2
7.9 in2
1.0 in2
 one month ago
 one month ago
sierraurb Group Title
PLEASE HELP!! A rain gutter is to be constructed of aluminum sheets 12 inches wide. After marking off a length of 4 inches from each edge, this length is bent up at an angle Θ. The area A of the opening may be expressed as the function: A(Θ) = 16 sin Θ • (cos Θ + 1). If Θ = 90°, what is the area of the opening? When i plug 90 in i keep getting 15, but my choices are: 21.8 in2 16.0 in2 7.9 in2 1.0 in2
 one month ago
 one month ago

This Question is Closed

sierraurb Group TitleBest ResponseYou've already chosen the best response.0
@dangerousjesse any luck?
 one month ago

sierraurb Group TitleBest ResponseYou've already chosen the best response.0
@phi @vineeth10
 one month ago

sierraurb Group TitleBest ResponseYou've already chosen the best response.0
@ganeshie8 @MATHMALE
 one month ago

phi Group TitleBest ResponseYou've already chosen the best response.1
first, you can do this without a calculator. But if you do use a calculator, be sure it is in degree mode. you should(!) know sin(90º)= 1 and cos(90º)= 0
 one month ago

sierraurb Group TitleBest ResponseYou've already chosen the best response.0
@phi i just figured it out actually!! C right? and could you please help me with one more!! im stuck on it :/
 one month ago

sierraurb Group TitleBest ResponseYou've already chosen the best response.0
Simplify \[\sqrt{\left( 1\sin \Theta \right)\left( 1+\sin \Theta \right)}\]
 one month ago

sierraurb Group TitleBest ResponseYou've already chosen the best response.0
@phi i have no idea what to do
 one month ago

phi Group TitleBest ResponseYou've already chosen the best response.1
First, How did you get C 7.9? It seems if sin(90) is 1 and cos(90) is 0 you would do 16 sin Θ • (cos Θ + 1) 16 • 1 •(0+1) and now we add 0+1 (not *too* hard) and multiply that by 16*1 you don't get 7.9
 one month ago

sierraurb Group TitleBest ResponseYou've already chosen the best response.0
For some reason i divided 16 in 2 idk why haha thank you!!
 one month ago

phi Group TitleBest ResponseYou've already chosen the best response.1
any idea what the answer is for your first question?
 one month ago

sierraurb Group TitleBest ResponseYou've already chosen the best response.0
b right?
 one month ago

sierraurb Group TitleBest ResponseYou've already chosen the best response.0
any idea on how to solve the second one? i really have no idea what to do @phi
 one month ago

phi Group TitleBest ResponseYou've already chosen the best response.1
do you know how to multiply the two binomials inside the square root (some people use FOIL)
 one month ago

phi Group TitleBest ResponseYou've already chosen the best response.1
if you don't see http://www.khanacademy.org/math/algebra/multiplyingfactoringexpression/multiplyingbinomials/v/multiplyingbinomials
 one month ago

sierraurb Group TitleBest ResponseYou've already chosen the best response.0
yeah when i foil i get sqrt(1sin O)
 one month ago

sierraurb Group TitleBest ResponseYou've already chosen the best response.0
is that right? @phi
 one month ago

phi Group TitleBest ResponseYou've already chosen the best response.1
can you show your work?
 one month ago

sierraurb Group TitleBest ResponseYou've already chosen the best response.0
F: 1*1=1 O: 1*sinO=sinO I: sinO*1=sinO L: sinO*sinO=sin2 so its sqrt(1sin^2) oops!
 one month ago

sierraurb Group TitleBest ResponseYou've already chosen the best response.0
these are my options btw @phi ±sin Θ cos Θ ±tan Θ square root sine theta
 one month ago

phi Group TitleBest ResponseYou've already chosen the best response.1
ok looks better there is a *very useful* identity you should remember for trig problems \[ \sin^2 x + \cos^2 x = 1 \] which you can rewrite as \[ \sin^2 x = 1  \cos^2 x \] or \[ \cos^2 x= 1  \sin^2 x \]
 one month ago

sierraurb Group TitleBest ResponseYou've already chosen the best response.0
would it be B?
 one month ago

phi Group TitleBest ResponseYou've already chosen the best response.1
yes. replace 1 sin^2 with cos^2 inside the square root sqrt(cos^2) = cos is the only choice that looks close (they must only want the positive root)  cos Θ 
 one month ago

sierraurb Group TitleBest ResponseYou've already chosen the best response.0
@phi thank you so so much!! i really truly appreciate it :)
 one month ago
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