Angles α and β are angles in standard position such that: α terminates in quadrant ii and sinα = 3/5, β terminates in quadrant i and cosβ = 4/5 find cos(α + β).

We are given

Angles α and β are angles in standard position

and

α terminates in Quadrant II

β terminates in Quadrant I

and we have

we can use triangle and find cos(α)

we get

and we have

we can draw triangle

now, we can use formula

now, we can plug values

now, we can simplify it

...............Answer

answer: i'm not going to give you the answer, but some hints to work it out.

step-by-step explanation: so, if there is a straight line that means that the line angle is 180°. so we subtract the 2 angle measures provided, (15 and 38) from 180. so the answer is 180 - (38 + 15). (you have to solve the equation)