Math help!

[kING701]

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for the math section i forget how to do these types of questions:

cos116 = ??

All i remember is CAST.

also how do u determine co-terminal angles in radians? (add and subtract 2pi??)
any help appreciated!

 

[z3u2]

for the math section i forget how to do these types of questions:

cos116 = ??

try a calculator!😎

 

[DamienPro]

for the math section i forget how to do these types of questions:

cos116 = ??

All i remember is CAST.

also how do u determine co-terminal angles in radians? (add and subtract 2pi??)
any help appreciated!

cos 116 = - cos 26

since cos 30 = sqrt (3)/2 and cos 0 = 1

You just have to pick an answer between -1 and -0.866

Your statement on co-terminal is the right one.

 

[richard86]

isn't this Q from the destroyer?? I remember it.. anyways look for the reference angle.. 116 degrees passes the 90 degree mark right? so.. 180-116= 64 degrees. so cos 116 is equal to cos 64. however, you must use CAST like you said. this means starting from quadrant 4, write CAST counterclockwise. C=cos is positive here, A means all in Q1 are +, S means all in Q2 are +, T means all in Q3 are +. so ur cos 64 actually becomes -cos64.


therefore, cos 116= -cos64

 

[DamienPro]

cos 116 = - cos 26

since cos 30 = sqrt (3)/2 and cos 0 = 1

You just have to pick an answer between -1 and -0.866

Your statement on co-terminal is the right one.

Oops ... my bad😛.

So, cos 116 = - cos 64

since cos 60 = 0.5 and cos 90 = 0

Answer will be: -0.5 < x < 0 with x closer and tending to -0.5 which is something like -0.4...

 

[z3u2]

Oops ... my bad😛.

So, cos 116 = - cos 64

since cos 60 = 0.5 and cos 90 = 0

Answer will be: -0.5 < x < 0 with x closer and tending to -0.5 which is something like -0.4...

oh, was the question only asking for an approx value??
i thought it was looking for the exact value..
which u probably can only do it with a calculator

anyhow, if just looking for a range, i'd draw a cosine graph. You can instantly find out it's between -0.5 and 0 .

 

[Streetwolf]

I doubt you get a question like that. Probably something with an exact answer.