# How to prove cos^2theta + sin^2theta = 1 ?Please no short answers, a good answer with explanation !

2
by Robotman

2014-06-25T14:31:10+05:30
This is very simple, in the image attached, you can see for the angle theta in the right angled triangle, AC is the p [perpendicular], BC is the b [base] and AB is h [hypotenuse].
Cos^2theta + sin^2 theta can be written as :-
..........[because cos theta = b/h and sin theta = p/h]
So, since b^2 + p^2 = h^2 [pythagoras theorem], we can write  as h^2/h^2 = 1.
Hence proved
sorry I forgot to attach the image
Okay, I got it, thanks !
:)
2014-06-25T14:51:42+05:30
Sin α =

cos α=

becuse acc. to pythagorus theorm

hence

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