#Negative exponent on sine

36 messages · Page 1 of 1 (latest)

vital oreBOT
unborn turtle
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sin^-1(x) is usually reserved for arcsin, the inverse of sin

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but otherwise the exponent laws youre applying are fine

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(sin(x))^(-1)=cosec(x)

bright dune
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So I can’t do what I did if it involves sin, cos or tan

unborn turtle
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youre better off writing 1/sin or something like that, or people can easily get confused

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any other exponent is fine

bright dune
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Thank you

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But is there a way to express sin(x) to the power of -1?

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Or is that not a thing

orchid flicker
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1/cscx ?

unborn turtle
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cosec(x)=1/sin(x)

orchid flicker
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= 1/1/sinx = sinx

unborn turtle
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wifi being slow as hell

bright dune
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Oh the secants are above my level 😢

unborn turtle
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the trig functions all have reciprocals
cosec=1/sin sec=1/cos cot=1/tan

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thats the only way to write it unless you specify like (sin(x))^(-1)

bright dune
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Can you use the chain rule for the derivative of those

unborn turtle
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that im aware of anyway

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of course

bright dune
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Okay awesome

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Thank you for your help

unborn turtle
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np

indigo geyser
worn leafBOT
indigo geyser
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I think the difference here, in mathematical language, is the $\sin$ is a known to be a function. That means that $\sin^{-1}$ is understood to be the $\textit{inverse of a function}$, and NOT the reciprocal. Whereas $(\sin x)$ is known to be a number, so $(\sin x)^{-1}$ is known the be the reciprocal of that number. The same rule should apply for any function. A math student should know the difference between $f^{-1}(x)$ and $(f(x))^{-1}$

worn leafBOT
indigo geyser
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But I've read a few math books that have argued against using $f^{-1}$ for this exact reason, but a better notation has not been adopted yet.

worn leafBOT
indigo geyser
bright dune
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In my country it is common to use f and then in subscript “inv” for an inverse function

unborn turtle
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ive never seen that one beforecatthink

uncut tide
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I solved the problem for me. What do sin(x)^2, sin(x)^-1, sin(x^2), and asin(x) all mean? If you know what each one means, problem solved.

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Never write sin^-1(x), and never write sin^2(x). Is sin^2(x) the square of the sine of x, or is it the sine of the sine of x? Is sin^-1(x) the reciprocal of the sine of x, or is it the arcsine of x? I don't know, and I don't care. The problem "What's 6/2*3?" can also go in the grave. No notation in this message is clear, and never use it.

gloomy wedge
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