Motion of a Projectile

[nycmath]

Precalculus
Michael Sullivan
Edition 10
Chapter 3, Section 3.4

Question 12 Part 1

[nycmath]

Question 12 Part 2

[nycmath]

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[nycmath]

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[nycmath]

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[nycmath]

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This is 12F.

[Eigenvalue]

Your thinking is correct, however, the vertex has an x-value of 15.625, rather than 156.25. I can redo parts A, B, and C--which are affected by the vertex value.

[Guest]

Good catch by Eigenvalue - the vertex is at x = -b/(2a) = 15.625, and the extra zero in 156.25 is exactly the kind of slip that is easy to miss when the algebra "looks right".

One habit that catches these: graph the height function on your TI-84 and check the table values around your computed vertex. In split-screen graph-table mode you can watch the y-values peak right at x = 15.625, and you would immediately see that at x = 156.25 the height is already negative - the projectile landed long ago. This TI-84 split-screen graph-table tutorial shows how to set that mode up.

[nycmath]

Your thinking is correct, however, the vertex has an x-value of 15.625, rather than 156.25. I can redo parts A, B, and C--which are affected by the vertex value.

If you want to redo parts A, B, and C, please do so.