Wednesday, October 16, 2013

Trigonometry on the Calculator

I came up with a memory tool that I hope will help the kids remember which process to use when solving/evaluating on the calculator:

csc ____ = 5    versus     csc 25 =____

It all seems to get jumbled up together in their heads after they learn various equations on the calculator.

Entering either one on the calculator involves a reciprocal somehow, and they mix up when to reciprocate. For the first one:

 csc ____ = 5     you enter:   sin -1 (1/5)

For the second one:

 csc 25 =____     you enter:   1 / sin (25)

Here's what I hope will stick:

For the first one:

csc ____ = 5     the BLANK is in the MIDDLE,
so the RECIPROCAL is in the MIDDLE   sin -1 (1/5)

For the second one:

 csc 25 =____     the BLANK is on the OUTSIDE,
so the RECIPROCAL is on the OUTSIDE   1 / sin (25)

Many more ways to mess up, but maybe this will fix one problem.

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