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Mathematics 16 Online
OpenStudy (anonymous):

Fan and Medal!!!

OpenStudy (anonymous):

simplify \[(1-\cos(\Theta)(1+\cos(\Theta)/(1-\sin(\Theta)(1+\sin(\Theta)\]

OpenStudy (anonymous):

(1 - cos(theta))(1 + cos(theta)) -------------------------- (1 - sin(theta))(1 + sin(theta))

OpenStudy (anonymous):

a. sin^2(theta) b. cos^2(theta) c. tan^2(theta) d. cos(theta) / sin(theta)

OpenStudy (anonymous):

Do you know how to multiply the numerator together? aka distribute the fraction

OpenStudy (anonymous):

I have no clue when I comes to trig

OpenStudy (anonymous):

this problem is the same as (2-x) (2+x) for example. Do you know how to multiply this out? ^^^^^

OpenStudy (anonymous):

yeah, 4 + 2x - 2x - x^2

OpenStudy (anonymous):

-x^2 + 4

OpenStudy (anonymous):

good now think, when cos(x) times cos(x) it becomes cos(x) squared , or we write as cos^2x

OpenStudy (anonymous):

1 + cos(theta) - cos(theta) - cos(theta)^2

OpenStudy (anonymous):

-cos(theta)^2 + 1

OpenStudy (anonymous):

-sin(theta)^2 + 1

OpenStudy (anonymous):

d??

OpenStudy (anonymous):

good! :) just leave it as 1-cos^2 theta / 1-sin^2theta then you know that sin^2x + cos^2x = 1 1-cos^2x = sin^2x 1-sin^2x = cos^2x

OpenStudy (anonymous):

not yet! Plug those in first. Not D :))

OpenStudy (anonymous):

what do I plug them into??

OpenStudy (anonymous):

you know that 1-cos^2theta = sin^2 theta, so replace the numerator of 1-cos^2 theta/1-sin^2 theta with sin^2 theta the we'd get sin^2 theta/1-sin^2 theta

OpenStudy (anonymous):

do you know the formular sin^2 theta + cos^2 theta = 1? That's where we can use to plug in

OpenStudy (anonymous):

so its now tan^2(theta)?? or sin^2(theta)? I remember that formula

OpenStudy (anonymous):

Yes! tan^2 theta!! Correct! because sin^2 theta / cos^2 theta = tan^2 theta sin/cos = tan

OpenStudy (anonymous):

oh yeah!!! I got it from a previous lesson. thanks so much!!

OpenStudy (anonymous):

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OpenStudy (anonymous):

do u mind helping me out with another question please?

OpenStudy (anonymous):

Yes, sure :)

OpenStudy (anonymous):

thanks. one sec

OpenStudy (anonymous):

The temperature of a chemical reaction ranges between 30°C and 70°C. The temperature is at its lowest point when t = 0 and completes one cycle over a 10-hour period. What is a sine function that would model this reaction?

OpenStudy (anonymous):

a. f(t) = 20 sin 10t + 50 b. f(t) = 50 sin 10t + 20 c. f(t) = 50 sin pi/5t + 20 d. f(t) = 20 sin pi/5t + 50

OpenStudy (anonymous):

I think its c but im not sure

OpenStudy (anonymous):

Hm it's not C. Here's an easy way to think about this

OpenStudy (anonymous):

what's sin of 0?

OpenStudy (anonymous):

0

OpenStudy (anonymous):

Quote (chemical reaction RANGES between 30°C and 70°C. The temperature is at its lowest point when t = 0 ) Let's say you think it's C. f(0) = 0 + 20 It says range from 30 TO 70 . The equation MUST NOT go below 30 degrees. So C and the other answer with 20 degrees at the end is wrong.

OpenStudy (anonymous):

So now you eliminate 2 answers. All that's left is to figure out the B value

OpenStudy (anonymous):

i thought it couldn't be a or d. since the amplitude is 20?

OpenStudy (anonymous):

wow im stupid sorry, your right thanks so much

OpenStudy (anonymous):

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