Hey there, I'm using a Ti-84 calculator to calculate derrivatives.(adsbygoogle = window.adsbygoogle || []).push({});

It goes like this:

Y1={the actual function}

Y2=nDeriv(Y1,X,X)

This seems to work, except for functions with cos(x), sin(x),..

Example:

Y1=X²

Y2=nDeriv(Y1,X,X)

Y3=2X

As Y3 represents the actual derrivative of Y1, Y2 and Y3 are the same.

But when I enter the following:

Y1=sin(X)

Y2=nDeriv(Y1,X,X)

Y3=cos(x)

As cos(x) is the derrivative of sin(x), Y2 and Y3 should be the same. But they aren't.

For X=3, I get:

Y1=0.258819045103

Y2=0.016858586

Y3=0.965925826289

Does anyone have an idea what I'm doing wrong? Thanks in advance.

E: I think I found the solution myself. It seems that X was considered as a degree value instead of a radian value!

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# Ti-84 strange derrivative problem

Can you offer guidance or do you also need help?

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