THE TRICK | ||||||||||||||
To learn the derivatives of the 6 trig functions you actually only have to learn 3 of them. The three to learn are sine, tangent, and secant. |
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The other three functions all start with "co": Cosine, Cotangent, and Cosecant. Think of the functions as having partners: |
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To find the derivative of the "co" functions, start with the derivatives of sine, tangent and secant, change each function in the derivative to it’s co-function partner and put a minus sign in front of the derivative. |
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So starting with one of the three we need to know: If F(x) = secant X then F'(x) = secant X tangent X
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So now to get the derivative of the cosecant: If F(X) = cosecant X then F'(X) = -cosecant X cotangent X |
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So all 6 trig function derivatives look like this: |
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Thanks to Bruce Kirkpatrick for this.





