Question

Find the exact value of sin55°cos25°+cos55°sin25°

Answer 1

I have a feeling the 25 may be 35 ??? WE can find and exact value then

Answer 2

@jim_thompson5910 any ideas?

Answer 3

sorry I don't know

all I know is that

sin55°cos25°+cos55°sin25° = sin(80°)

I used the identity

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

Answer 4

I don't know how to find the exact value of sin(80°) in terms of radicals

Answer 5

@welshfella has a good point, if the 25 was 35, then

sin55°cos35°+cos55°sin35° = sin(55+35) = sin(90°) = 1