Use a graphing calculator to solve the equation -3 cos t = 1 in the interval from 0 to 2p. Round to the nearest hundredth.

Question

Use a graphing calculator to solve the equation -3 cos t = 1  in the interval from 0 to 2p. Round to the nearest hundredth.

anonymous · Answer

I typed it in on my calculator but did not do a thingg!

swissgirl · Answer

$\cos(t)=\large{1 \over- 3} $
$\cos^{-1}(\large{1 \over- 3} )=t$

anonymous · Answer

How did you get that?

swissgirl · Answer

First I divided -3 from both sides

swissgirl · Answer

$-3\cos(t)=1$

$\large {-3\cos(t) \over -3}={1 \over -3}$

$\cos(t)=\large{1 \over -3}$

$\cos^{-1}(\cos(t))=Cos^{-1}(\large{1 \over -3})$

$t=Cos^{-1}(\large{1 \over -3})$

anonymous · Answer

How would you put this in a decimal form.?

swissgirl · Answer

lol you gotta put this into your calc first and then your answer will be a decimal

anonymous · Answer

Oh wow that was dumb of me lol. I was thinking this had to be put in a decimal form.! before solving it

anonymous · Answer

I got 109.47

swissgirl · Answer

Are you supossed to be working in radians or degrees?

anonymous · Answer

Ah, I had my calc set in degrees, I'm pretty sure I'm suppose to be using radians.! Gah I keep forgetting to change the mode

anonymous · Answer

Ok now I got 1.91.!

swissgirl · Answer

YUP THAT IS WHAT I GOT :)

anonymous · Answer

Thanks for the help.! (-: