SOLUTION: Sin x = 1/3 ,0 < x < pi/2 Cos y = 2/5 ,0 < x

SOLUTION: Sin x = 1/3 ,0 < x < pi/2 Cos y = 2/5 ,0 < x < pi/2 Find sin (x+y)

Question 989696: Sin x = 1/3 ,0 < x < pi/2
Cos y = 2/5 ,0 < x < pi/2
Find sin (x+y)
Answer by ikleyn(52781) (Show Source): You can put this solution on YOUR website!
.
Use the addition formula for sines:

sin(x+y) = sin(x)*cos(y) + cos(x)*sin(y) (1)

(see for example the lessons FORMULAS FOR TRIGONOMETRIC FUNCTIONS and Addition and subtraction formulas in this site,
or any systematic textbook in Trigonometry).

Notice that, since sin(x) = , cos(x) = = = = ..

Also notice that, since cos(y) = , sin(y) = = = = ..

Now substitute these expressions into the formula (1).

Good luck.

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