Question

Solve sin (x+y) = cos(x-y)

Answer 1

Answer:

solution

sin (x+y) can be written as cos [ 90-(x+y ] [ sin x = cos (90-x) ]

therefore we can rewrite the given expression as

cos [ 90-(x+y) ] = cos (x - y)

=> 90 - (x+y) = (x - y)

=> 90 = (x - y)+(x + y) [ by transposing -(x + y) to the right hand side ]

=> 90 = x - y + x + y

=> 90 = 2x

=> x = 45°

=> y = 0°

Answer 2

Answer:

Step-by-step explanation:

sin(x+y)=sin(90°-(x-y))..........(1)

x+y =90°-x+y..........(1)

x=90°-x ⇒x+x=90°

2x=90°⇒x=45°

x+y=x-y

45°+y=45°-y⇒y=-y

2y=0

y=0