I only memorized these trigonometric differential identities :(adsbygoogle = window.adsbygoogle || []).push({});

`sin(x) = cos(x)

`cos(x) = -sin(x)

because I can convert tan(x) to sin(x) / cos(x) and

sec(x) to 1 / cos(x) .. etc

And there is no need to memorize some integral identities such as :

∫ sin(x) dx = -cos(x) + C

∫ cos(x) dx = sin(x) + C

because I memorized

`sin(x) = cos(x)

`cos(x) = -sin(x)

But these identities seem inevitable to memorize:

∫ sec^2(x) dx = tan(x) + C

∫ cosec^2(x) dx = -cot(x) + C

∫ sec(x)tan(x) dx = sec(x) + C

∫ cosec(x)cot(x) dx = -cosec(x) + C

For example

∫ sec^2(x) dx = tan(x) + C

First I tried to convert sec^2(x) to 1 / cos^2(x)

∫ sec^2(x) dx = ∫ (1 / cos^2(x)) dx

And that's where I'm stuck.

It looks impossible to proceed anymore without memorizing a trigonometric differential identity

`tan(x) = sec^2(x)

**Physics Forums - The Fusion of Science and Community**

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Should I memorize all these trigonometric integrals?

Tags:

Loading...

Similar Threads - Should memorize trigonometric | Date |
---|---|

I Should we consider negative axis when finding the volume? | Dec 21, 2016 |

Which vectorial norm should I use? | Dec 4, 2015 |

How important is memorizing proof? | Nov 10, 2013 |

Can it be argued that derivatives should be undefined? | Jun 4, 2013 |

My satellite should go in a circle, not an ellipse | Aug 31, 2011 |

**Physics Forums - The Fusion of Science and Community**