Question

plz tell solution plz

Answer 1

Hey !

Solution:

Well this is a trigonometric problem, hence we would be using trigonometric identities to solve this problem.

Formula to be used = Sin ( A + B ) = Sin A . Cos B + Cos A . Sin B

So Sin 75 can be written as Sin ( 30 + 45 )

=> Sin 75 = Sin ( 45 + 30 ) = Sin 45 . Cos 30 + Cos 45 . Sin 30

Values of some functions :

Sin 45 = 1 / √2 ; Cos 45 = 1 / √2 ; Sin 30 = 1 / 2 ; Cos 30 = √3 / 2

So substituting the above values in the equation we get,

Sin ( 45 + 30 ) = ( 1 / √2 * √ 3 / 2 ) + ( 1 / √2 * 1 / 2 )

=> Sin ( 45 + 30 ) = √3 / 2√2 + 1 / 2√2

=> Sin ( 45 + 30 ) = ( 1 + √3 ) / 2√2

So Sin 75 = ( 1 + √3 ) / 2√2 , which is approximately 0.96

Hope my answer helped !

Answer 2

hello mate!....
$given..... \\ \sin(75) \\ \sin(75) = \sin(40 + 35) \\ \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: = \sin(4 5 ) . \cos(30) + \cos(45) .sin(30) \\ \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: = \frac{1}{ \sqrt{2} } \times \frac{ \sqrt{3} }{2} + \frac{1}{ \sqrt{2} } \times \frac{1}{2} \\ \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \sin(75) = \frac{ \sqrt{3} + 1 }{2 \sqrt{2} } \\ hope \: it \: helps \: u \: dear..........$