Answer:
cos B = 8/17
Step-by-step explanation:
The cosine function is defined as (adjacent side) / (hypotenuse), and in this case is 8/17.
The measure of the third side must be less than the sum of the other two. That property is valid for all triangles.
For this question, call x the measure of the third side. So you must have
x < 4 + 3
x < 7 ft
The only option that satisfies the condition above is
option A) 5 ft.
I hope this helps. =)
Looks like a badly encoded/decoded symbol. It's supposed to be a minus sign, so you're asked to find the expectation of 2<em>X </em>² - <em>Y</em>.
If you don't know how <em>X</em> or <em>Y</em> are distributed, but you know E[<em>X</em> ²] and E[<em>Y</em>], then it's as simple as distributing the expectation over the sum:
E[2<em>X </em>² - <em>Y</em>] = 2 E[<em>X </em>²] - E[<em>Y</em>]
Or, if you're given the expectation and variance of <em>X</em>, you have
Var[<em>X</em>] = E[<em>X</em> ²] - E[<em>X</em>]²
→ E[2<em>X </em>² - <em>Y</em>] = 2 (Var[<em>X</em>] + E[<em>X</em>]²) - E[<em>Y</em>]
Otherwise, you may be given the density function, or joint density, in which case you can determine the expectations by computing an integral or sum.
