Pre-cal 12

What are the restrictions or non-permissible values for this identity?

cos^2 x = cot x . sin x / sec x

Question

Pre-cal 12




What are the restrictions or non-permissible values for this identity?


cos^2 x = cot x . sin x / sec x

loser66 · Answer

when using cot, you have to make sure that sin x is NOT 0, that is x is NOT 0 or (2k+1) pi
that is one of restriction. 
You do the same for sec.

korosh23 · Answer

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@Loser66 you mean this one?

why cos x is not restricted?

korosh23 · Answer

the cos x at the bottom

loser66 · Answer

Yes, it is. That is why I said YOU do the restriction for sec. I let you take over that part.

korosh23 · Answer

so you mean cos x is restricted too?

korosh23 · Answer

because my teacher only told me  that sin x is restricted not cosx

korosh23 · Answer

I am confused, could you please clarify this for me?

loser66 · Answer

I don't know. I was taught that sec is undefined when x = 90, 270 ,.....
Hence when using sec at the denominator, we must restrict those values.

korosh23 · Answer

ok I will ask this from my teacher, but thanks for sharing it. :)