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I have a problem similar to : http://physics.mercer.edu/balduz/GenPhys/HRW7probs/03vectors/3-048.pdf

If A = 10i and 1.63j, what's the next step to finding magnitude and direction? Does it involve multiplying sin/cos? In what combo? What about tan inverse?

user366783
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    Standard hints for dealing with vectors: (1) Break into components. (2) Draw a picture. (3) Make one or more right triangles. (4) Pythagorean theorem and soh-cah-toa. –  Sep 22 '16 at 01:08
  • Is direction found by y/x times tan inverse? That isn't working with my homework problem. I don't understand why. http://imgur.com/a/dMTOd – user366783 Sep 22 '16 at 01:35
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    Do you mean $\arctan\left(\frac{y}{x}\right)$? If so, you should know that $\arctan$ only really works in the $1$st and $4$th quadrants. In the $2$nd and $3$rd you have to add $\pi$ (or $180$ if you're working in degrees) to whatever answer your calculator gives you. –  Sep 22 '16 at 01:39
  • I have to add 3.14? – user366783 Sep 22 '16 at 01:40
  • Okay. It worked. Thanks. – user366783 Sep 22 '16 at 01:43
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    KhanAcademy has an explanation for why you need to add $\pi$. –  Sep 22 '16 at 01:43

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