Proof of sen² 25º + cos² 45º + sen² 65º = 3/2

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The discussion focuses on proving the equation sin² 25º + cos² 45º + sin² 65º = 3/2. Participants clarify that "sen" is a mispronunciation of "sin," and the notation sin² x indicates the sine of x squared. The value of cos 45º is confirmed to be 1, which is relevant for the proof. There is some confusion regarding the notation, but it is explained that it simplifies writing. The conversation emphasizes understanding the squared terms in trigonometric functions.
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Homework Statement


Show that sen² 25º + cos² 45º + sen² 65º = 3/2



Homework Equations


cos 45º= 1


The Attempt at a Solution


I get confused with the ² on the cos and sen...
 
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Hi Fanekaz! :smile:

(btw, it's sin, not sen :wink:)
Fanekaz said:
I get confused with the ² on the cos and sen...

It just means that the whole thing is squared …

so sin2x means (sinx)2 …

(pronounce it "sine squared of x")

it saves writing brackets. :biggrin:​
 

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