Question

find the value of following without using table sin 75 sin 105​

Answer 1

Answer:

0.48296

Step-by-step explanation:

let I =

$\sin(75) \times \sin(105)$

$0.5 \times 2 \times \sin(75) \times \sin(105)$

$0.5 \times ( \cos((105 - 75) \div 2) - \cos((75 + 105) \div 2) )$

$0.5 \times ( \cos(15) - \cos(90) )$

$0.5 \times \cos(15)$

$0.48296$

You Can Find The Value of cos 15 by the formula

cos (45 -15) .

Answer 2

Answer:

1 + 2√3 whole divide by 4

Step-by-step explanation:

=sin(75)sin(105)

=sin (30 + 45 ) . sin (90 + 45 )

=sin30.cos45 + cos30.sin45. ( sin90.cos45 + cos90.sin45. )

=1/2×√3/2 + 2/√3×√3/2 ( 1×√3/2 + 0×√3/2 )

1/4 + 1 . ( √3/2 +0 )

1/4 + √3/2

2+4√3 whole divide by 8

1 + 2√3 whole divide by 4. ans.