## Homework Statement

how would you write cosine(.9812) in two ways expressed with radians
(calculator based)

cos-1(x)

## The Attempt at a Solution

i just plugged cos-1(.9812) and got .1942 radians. If this is one of the answers how do i find the other.

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chiro

## Homework Statement

how would you write cosine(.9812) in two ways expressed with radians
(calculator based)

cos-1(x)

## The Attempt at a Solution

i just plugged cos-1(.9812) and got .1942 radians. If this is one of the answers how do i find the other.
I'm not completely sure what you are asking. cos(x) is a function and only spits out one answer for for any given x. So you will only ever get one answer which means it is basically the same value even if you write it in two different ways.

Mark44
Mentor

## Homework Statement

how would you write cosine(.9812) in two ways expressed with radians
(calculator based)
Do you mean cos-1(.9812)? That's what your work below suggests.

cos-1(x)

## The Attempt at a Solution

i just plugged cos-1(.9812) and got .1942 radians. If this is one of the answers how do i find the other.
cos(.1942 radians) $\approx$ .9812, but there are many angles whose cosine is also .9812. The cosine function is periodic, with period 2π, so adding 2π or integer multiples of 2π gives you an angle with the same cosine value. The cosine function is also and even function, which means that cos(-x) = cos(x), for any real x.

alright. Thanks!