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Mathematics 8 Online
OpenStudy (anonymous):

how do you factor a trigonometric function

OpenStudy (campbell_st):

well it depends what it looks like if you had 2sin^2(x) + 3sin(x) + 1 = 0 it factors like a quadratic (2sin(x) + 1)(sin(x) + 1) = 0 etc..

OpenStudy (dumbcow):

same way you factor a polynomial function, instead of variables you have trig functions

OpenStudy (anonymous):

thanks guys, i already figured out how, sorry to waste your time

OpenStudy (anonymous):

but i do need help with something else

OpenStudy (anonymous):

Find sin θ if cot θ = - 4 and cos θ < 0. no answer please, i just want to know how to do it, if you do have the answer please show the steps

OpenStudy (dumbcow):

ok for these type of problems I like to draw a triangle first determine which quadrant theta is in: cos < 0 --> Q2,Q3 cot <0 so tan <0 --> Q2,Q4 therefore we are in Q2 so sin is positive |dw:1406268431754:dw|

OpenStudy (anonymous):

so 1 over sqrt of 17 right?

OpenStudy (dumbcow):

correct

OpenStudy (anonymous):

but thats not an option

OpenStudy (dumbcow):

well im 100% sure it is correct so either the textbook is in error or its written a different way

OpenStudy (dumbcow):

do you know how to rationalize the denominator (get rid of the sqrt)

OpenStudy (anonymous):

they have sqrt of 17 over 4?

OpenStudy (dumbcow):

no that is not equal to 1/sqrt17

OpenStudy (dumbcow):

\[\frac{1}{\sqrt{17}}*\frac{\sqrt{17}}{\sqrt{17}} = \frac{\sqrt{17}}{17}\]

OpenStudy (anonymous):

they have that

OpenStudy (anonymous):

thanks

OpenStudy (dumbcow):

yw

OpenStudy (anonymous):

do you think you could help me with one more problem

OpenStudy (dumbcow):

ok but if its similar i will refer you to my answer to this problem

OpenStudy (anonymous):

ok

OpenStudy (anonymous):

quantity cosecant of x to the power of two times secant of x to the power of two divided by quantity secant of x to the power of two plus cosecant of x to the power of two.

OpenStudy (anonymous):

csc^2(x) * sec^2(x) /sec^2 (x) + csc^2(x)

OpenStudy (anonymous):

simplify

OpenStudy (dumbcow):

ok start by substituting csc = 1/sin sec = 1/cos then combine the fractions in the denominator

OpenStudy (anonymous):

but isnt that only if they werent squared

OpenStudy (dumbcow):

doesn't matter csc^2 = 1/sin^2 sec^2 = 1/cos^2

OpenStudy (anonymous):

ok and that equals 1

OpenStudy (dumbcow):

well sin^2 + cos^2 = 1, is that what you mean?

OpenStudy (anonymous):

yes

OpenStudy (anonymous):

and 1/1 =1

OpenStudy (anonymous):

now its 1/sce^2(x)*csc^2(x) right

OpenStudy (dumbcow):

no you lost me csc^2 +sec^2 is not the same as sin^2 +cos^2

OpenStudy (dumbcow):

just sub everything in and work through it step by step

OpenStudy (anonymous):

no im talking about the denominator

OpenStudy (anonymous):

ok hld on let me try this

OpenStudy (dumbcow):

oh i see ....yes you got it however it should be 1/sin^2 cos^2

OpenStudy (anonymous):

ok thanks!

OpenStudy (dumbcow):

you are correct, answer is 1 sorry i hadn't worked it out yet

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