<span>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.</span>
Answer:
B
Step-by-step explanation:
Answer: 34
Step-by-step explanation: 4(7)+6
28+6 = 34
Since angles A and C are equivalent, then angles B and D must also be equivalent. So if
angle B = angle D then...
7x + 15 = 8x
Now we just solve for x
7x + 15 = 8x
15 = 8x - 7x
15 = x
We Can check to see if it is correct by substituting 15 in for x in the equation..
7x + 15 = 8x
7 (15)+15 = 8 (15)
105 +15 = 120
120 = 120
It checks! angles B and D = 120 degrees
Three times the result of a number plus a number equals two times a number minus a number.
or
Three times the result of a variable plus a variable equals two times a variable minus a variable.
