If sin(a+b)=4/5,sin(a-b)=5/13.Prove that 2a=63/16?

Question

a=alpha and b=bita-trigonometric

Answer 1

sin(a + b) = 4/5 --> a + b = arcsin(4/5)

sin(a - b) = 5/13 --> a - b = arcsin(5/13)

so

2a = arcsin(4/5) + arcsin(5/13)

2a = 1.322

which is not equal to 63/16

which does not equal 63/16

Answer 2

simple
take sine inverse on both side of both the equations
then U'll have
2 equations in a+b= Sin ^-1 (4/5)
and, a-b=Sin^-1 (5/13)
add them and u'll probably ave the result
haha

Answer 3

let Asin inverse of sin and then,
take sin inverse of sin(a+b) and sin a-b,then we have

Asin(sin(a+b))=a+b=Asin(4/5)=0.927295218---(1)
Asin(sin(a-b))=a-b=Asin(5/13)=0.39479112-----(2)
+
------------------------------------------------------------adding (1) and (2)
2a=1.322086338
but u told us to prove as 2a=63/16,that is equal to 3.9375
so, 2a is not equal to 63/16 and it is equal to 2a=1.322086338

Answer 4

Incomplete question

Answer 5

there is sth wrong with this question