Asked by hello :)

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

so i put it in a graphing calculator online and now i understand what i am supposed to write or do can someone please help me?
Answered by Reiny
-3 cos t = 1
first make sure your setting is in radians, look for a DRG key, press it
until you see RAD in your display.

simplify the equation to
cos t = -1/3

forget about the minus in -1/3 for the moment.
enter:
2ndF
cos
(1÷3)
=
to get 1.230959...
That would be you angle in "standard position", that is, the
corresponding angle if we had been in quadrant I
but since the cosine is negative we must be in quads II or III
so t = π - 1.230959.. = appr 1.9106
or
t = π + 1.230959.. = appr 4.3726

check my answer by plugging it in the original equation
Hint: it works
Answered by hello :)
i don't know where those displays is on the graphic calculator online but thank you for explaining it to me and giving me the answers.
Answered by Reiny
You don't really need a fancy graphic calculator like the TI-84, any cheap
scientific calculator has this stuff. I am using a 25 year old SHARP. I also have
one bought at a Dollar Store for $2.99, does the same thing.
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