Lydia graphed def at the coordinates d (-2, -1) , e (-2, 2), and f (0, 0) she thinks def is a right triangle. yes s lydia’s assertion correct?

No, Lydia's assertion is not correct

Step-by-step explanation:

Plot three Lydia's points D(-2, -1) , E (-2, 2), and F (0, 0) on the coordinate plane (see attached diagram).

Triangle DEF will be right triangle if one of its angle is right angle. If one angle is right angle, then adjacent sides are prependicular. If two sides are perpendicular, then the dot product is equal to 0.

1. Dot product between vectors DE and DF:

So, DE and DF are not perpendicular, and angle D is not right angle.

2.  Dot product between vectors ED and EF:

So, ED and EF are not perpendicular, and angle E is not right angle.

3. Dot product between vectors FD and FE:

So, FD and FE are not perpendicular, and angle F is not right angle.

hello from mrbilldoesmath!

answer:

a(n) - a(n-1) -3

discussion:

this ones a bit interesting. given a(n) = 5 - 3n consider this:

a(n-1) = 5 - 3(n-1)

          = (5 - 3n) + 3             => but a(n) = 5 - 3n, the first term

          = a(n)   + 3                 => subtract 3 from both sides

a(n-1) -3 = a(n)  

or

a(n) - a(n-1) -3

you,

mrb

46.2+112.3

step-by-step explanation: