Given |u| = 10 at ∠135° and |v| = 5 at ∠30°, what expression can be used to find |u + v|? (10)2 + (5)2 – 2(10)(5) cos(45°)
(10)2 + (5)2 – 2(10)(5) cos(75°)
(10)2 + (5)2 – 2(10)(5) cos(105°)
(10)2 + (5)2 – 2(10)(5) cos(165°)

B,

Step-by-step explanation:

Using the law of cosines, which is , you can simply insert all the values.

c=|u+v|

a= r value of u (10)

b= r value of v (5)

To find  C, you simply have to subtract v from u, and then subtract that number from 180 to find the reference angle.

I.E.: ∠135 - ∠30 = ∠105 ↔ 180 - 105 = 75 =  C

so, the completed equation would be 10^{2} + 5^{2}- 2(10)(5)cos(75)

b is the answer that makes most sense

step-by-step explanation: