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Mathematics 16 Online
OpenStudy (anonymous):

Use basic identities to simplify the expression.

OpenStudy (anonymous):

\[\frac{ \cos ^{2} \theta }{\sin ^{2}\theta } +\csc \theta \sin \theta \]

OpenStudy (anonymous):

answers are A. csc2θ B. sec2θ C. 1 D. tan2θ

OpenStudy (jdoe0001):

keep in mind that \(\bf tan(\theta)=\cfrac{sin(\theta)}{cos(\theta)}\qquad tan^2(\theta)=\cfrac{sin^2(\theta)}{cos^2(\theta)}\\ \quad \\ \quad \\ csc(\theta)=\cfrac{1}{sin(\theta)}\) so replace respectively

OpenStudy (jdoe0001):

notice that \(\bf csc(\theta)sin(\theta)\implies \cfrac{1}{\cancel{sin(\theta)}}\cancel{sin(\theta)}\)

OpenStudy (anonymous):

Also can someone \[\cos x-\sin ^{2}x-1\]Factor the algebraic expression below in terms of a single trigonometric function.

OpenStudy (anonymous):

the answer to the first one is D correct

OpenStudy (jdoe0001):

use the pythagorean identities

OpenStudy (anonymous):

the what?

OpenStudy (jdoe0001):

http://web.mit.edu/wwmath/trig/eq1.gif

OpenStudy (anonymous):

but how can u explain the second one

OpenStudy (jdoe0001):

notice the 1st identity if you solve for \(\bf sin^2(\theta)\) what would you get?

OpenStudy (anonymous):

|dw:1389052240284:dw|

OpenStudy (anonymous):

1?

OpenStudy (jdoe0001):

1? whatever happened to the cosine?

OpenStudy (anonymous):

oh yeah im so confused

OpenStudy (jdoe0001):

ok... lemme put it this way a + b = 1 solve for "a" what do you get?

OpenStudy (anonymous):

b-1

OpenStudy (anonymous):

1-b

OpenStudy (anonymous):

|dw:1389052562167:dw|

OpenStudy (anonymous):

positive?

OpenStudy (jdoe0001):

right, so \(\bf \begin{array}{llll} sin^2(\theta)+&cos^2(\theta)=&1\\ a+&b=&1\\ \end{array}\qquad \begin{array}{llll} \color{red}{sin^2(\theta)}=&1-&cos^2(\theta) \\a=&1-&b\\ \end{array}\\ \quad \\ \quad \\ cos(x)-sin^2(x)-1\implies cos(x)-[\color{red}{1-cos^2}]-1\)

OpenStudy (jdoe0001):

well. sorta missed, the "x", but anyhow, just distribute and simplify

OpenStudy (anonymous):

and the answer is csc^2(x)

OpenStudy (anonymous):

or (cosx+2) (cosx-1)

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