/sci/ - Science & Math

>>11105510
Oh god this shit confused the fuck out of me throughout physics I. They explain it so horribly.
It's because you're trying to find the components with respect to the given angle, not with respect to the x axis.
In cases like that, you need to dispose of your sin=y cos=x intuition, and instead return to the pythagorean definition of sin=O/H and cos=A/H.
Pic related.
Even though the *red* side of the triangle is aligned horizontally, it's the *opposite* side of the angle you're using to find the length-along-horizontal-axis of the hypotenuse. Thus, it's OPPOSITE/HYPOTENUSE=sin
Even though the *green* side of the triangle is aligned vertically, it's the *adjacent* side of the angle you're using to find the length-along-vertical-axis of the hypotenuse. Thus, it's ADJACENT/HYPOTENUSE=cos.

>>11105510
Oh god this shit confused the fuck out of me throughout physics I. They explain it so horribly.
It's because you're trying to find the components with respect to the given angle, not with respect to the x axis.
In cases like that, you need to dispose of your sin=y cos=x intuition, and instead return to the pythagorean definition of sin=O/H and cos=AH.
Pic related.
Even though the *red* side of the triangle is aligned horizontally, it's the *opposite* side of the angle you're using to find the length-along-horizontal-axis of the hypotenuse. Thus, it's OPPOSITE/HYPOTENUSE=sin
Even though the *green* side of the triangle is aligned vertically, it's the *opposite* side of the angle you're using to find the length-along-vertical-axis of the hypotenuse. Thus, it's ADJACENT/HYPOTENUSE=cos.