How do you apply the fundamental identities to values of #theta# and show that they are true?

1 Answer
Gió
Jan 9, 2015

I am not sure about this one but here I go;
you may try using angles that are "easy" to deal with, i.e., you know the values of the trigonometric functions associated with them,such as, #pi, pi/2, pi/3, pi/4, pi/3#.

Consider: #sin^2(theta) + cos^2(theta)=1#
Chose #theta=pi/3# (or 60○ if you like).
You have:
#sin(pi/3)=sqrt(3)/2#
#cos(pi/3)=1/2#

Substituting in #sin^2(theta)+cos^2(theta)# you get:
#3/4+1/4=1#

You may now use the same approach to all the other identities to check if they work.
I hope it helped.

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