Question

sin(a+b) = sin a cos b +cos a sin b

Answer 1

Answer:

Hi ,

Hi ,***************************

Hi ,***************************sin( A + B ) = sinAcosB + cosAsinB

Hi ,***************************sin( A + B ) = sinAcosB + cosAsinB**********************************

Hi ,***************************sin( A + B ) = sinAcosB + cosAsinB**********************************1 ) Here , we assume

Hi ,***************************sin( A + B ) = sinAcosB + cosAsinB**********************************1 ) Here , we assumeA = 45° , B = 30°

Hi ,***************************sin( A + B ) = sinAcosB + cosAsinB**********************************1 ) Here , we assumeA = 45° , B = 30°cos 15°

= cos ( 90 - 75 )

= cos ( 90 - 75 )= sin 75 °

= cos ( 90 - 75 )= sin 75 °= sin ( 45 + 30 )

= cos ( 90 - 75 )= sin 75 °= sin ( 45 + 30 )= sin45cos30 + cos45sin30

= cos ( 90 - 75 )= sin 75 °= sin ( 45 + 30 )= sin45cos30 + cos45sin30= ( 1/√2 )( √3/2 ) + ( 1/√2 ) ( 1/2 )

= cos ( 90 - 75 )= sin 75 °= sin ( 45 + 30 )= sin45cos30 + cos45sin30= ( 1/√2 )( √3/2 ) + ( 1/√2 ) ( 1/2 )= ( √3/2√2) + 1/2√2

= cos ( 90 - 75 )= sin 75 °= sin ( 45 + 30 )= sin45cos30 + cos45sin30= ( 1/√2 )( √3/2 ) + ( 1/√2 ) ( 1/2 )= ( √3/2√2) + 1/2√2= ( √3 + 1 )/2√2

= cos ( 90 - 75 )= sin 75 °= sin ( 45 + 30 )= sin45cos30 + cos45sin30= ( 1/√2 )( √3/2 ) + ( 1/√2 ) ( 1/2 )= ( √3/2√2) + 1/2√2= ( √3 + 1 )/2√2Therefore ,

cos15° = sin75° = ( √3 + 1 )/2√2

cos15° = sin75° = ( √3 + 1 )/2√2I hope this helps you.

cos15° = sin75° = ( √3 + 1 )/2√2I hope this helps you.: )

Answer 2

Formulas are in the attachment....Hope it helps...

I have added trick to remember it...hope you understand

Please mark me brainliest....