tan(15) =
sin(15) / cos(15) =
sin(45 - 30) / cos(45 - 30) =
[ sin(45)cos(30) - sin(30)cos(45) ] / [ cos(45)cos(30) + sin(45)sin(30)]

Since sin(45) = cos(45) = √2/2, you can just factor that out from the top and bottom
[ cos(30) - sin(30) ] / [ cos(30) + sin(30)]
[ √3/2 - 1/2 ] / [ √3/2 + 1/2]
(√3 - 1) / (√3 + 1)
(√3 - 1)^2 / (√3+1)(√3 - 1)
(√3 - 1)^2 / (3 - 1)
(3 - 2√3 +1) / 2
2 - √3

There's also a formula for tan(a-b), but I couldn't remember it off hand.

4 0

3 years ago

One month before the election, a poll of 630 randomly selected voters showed 54% planning to vote for a certain candidate. a wee

VikaD [51]

54% of 630 = 0.54 * 630 or approximately 340 of the 630 were planning to vote for the candidate.

51% of 1010 = 0.51 * 1010 or approximately 515 of the 1010 were planning to vote for the candidate.

This means that the voter support for this candidate increased.

7 0

3 years ago

Find the length of side y. y=_ft

jolli1 [7]

Answer: