I’m one who really hates memorizing formulas, be in as a student or tutor. So I shall share how I remember the three very useful trigonometry identities. I’ll start with the one which you all definitely can identify with.

sin^{2}x + cos^{2}x = 1

Credits: www.spikedmath.com
Credits: www.spikedmath.com

Now how do we get the other 2?

Simply divide the above equation by sin^{2}x and cos^{2}x respectively.
Lets divide by sin^{2}x!
\frac{sin^{2}x}{sin^{2}x} + \frac{cos^{2}x}{sin^{2}x} = \frac{1}{sin^{2}x}
Voila! we have 1 + cot^{2}x = cosec^{2}x

You can try to do the same with cos^{2}x! Let me know if you have problems!

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