Please i Find all solutions in radians in the range 2 2 su

Please

i) Find all solutions (in radians) in the range 2 < < 2 such that sin(2) = 0.3

ii) Find all solutions (in degrees) in the range 360 < < 360 such that cos(4) = cos()

I )

given sin(2) = 0.3

then sin(2) = -3/10

2 = sin^-1 ( -3/10 )

= 1/2 sin^-1 ( -3/10 )

==> - 1/2 sin^-1 ( 3/10 )

==> 0.30469/2 ==> 0.152345 radians

ii)

cos(4) = cos()

cos(4) - cos() = 0

we know cos ( s ) - cos ( t ) = - 2 sin ( s + t / 2 ) sin ( s - t /2)

therefore

-2sin ( 4 + /2 ) sin ( 4 - /2 ) = 0

2 sin ( 5 /2 ) sin( 3/2 ) = 0

sin ( 5 /2 ) sin( 3/2 ) = 0

sin ( 5 /2 ) =0; sin( 3/2 ) =0

( 5 /2 ) = 2 n ,where n=0,12.... 3/2 =2 n

=4 n / 5 , ( 2 + 4 n )/ 5 =4 n / 3 = ( 2 + 4 n )/ 3