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If sin (x-y)= 32\frac{\sqrt{3}}{2}23​​​ and cos (x+y)=12\frac1221​​ where x and y are positive acute angles and x ≥ y, then the value of x is:
Question

If sin (x-y)= 32\frac{\sqrt{3}}{2}​ and cos (x+y)=12\frac12​ where x and y are positive acute angles and x ≥ y, then the value of x is:

A.

70°

B.

60°

C.

30°

D.

50°

Correct option is B

Given:
sin (x-y)=32\text {sin (x-y)}= \frac{\sqrt{3}}{2}​​
cos(x+y)=12\cos (x+y) =\frac 12​​
Solution:
We know that:
sin (x-y)=32\text {sin (x-y)}= \frac{\sqrt{3}}{2}​ 

Since, sin60∘ = 32 \frac{\sqrt{3}}{2}
x-y= 60°60\degree..............(1)​
Similarly, we know:

cos(x+y)=12\cos (x+y) =\frac 12​​

Since, cos 60∘= 12\frac 12​​
x+y=60°.......(2)60\degree.......(2)​​
Add (1) and (2)
x-y=60°60\degree​​
x+y=60°60\degree
Adding these equations
(x-y)+(x+y)= 60°+60°60\degree +60\degree​​
2x=120°120\degree
x=60°60\degree​ ​​
The value of x = 60°60\degree​​

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