Question

Sin10°-cos10° product and evaluate​

Answer 1

$\\ \sf\longmapsto sin10°-cos10°$

$\\ \sf\longmapsto sin(90-10°)-cos10°$

• sin(90-A)=cosA

$\\ \sf\longmapsto cos10-cos10$

$\\ \sf\longmapsto 0$

Answer 2

Question should be sin 20 cos 10 + cos 20 sin 10

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

sin 20 cos 10 + cos 20 sin 10

= sin (20+10)

= sin 30

= 1/2