Calculus (help Steve plz)

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1) if w = <-8, 15>, find ||w||?

2) which expression is equivalent to (sin x+1) (sin x -1)?
A. Cos^2x
B. -cos^2x
C. Cos^2x+1
D. Cos^2x-1
E. -cos^2x-1

  • Calculus (help Steve plz) -

    1. whassup? just a simple vector
    |w| = √(8^2+15^2) = 17

    since (sin+1)(sin-1) = sin^2 - 1
    and cos^2 = 1-sin^2,

    you have -cos^2 x

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