Question

Prove: Sin15°/2.cos75°\2

Answer 1

sin15=sin(45−30)=sin45.cos30−sin30.cos45sin15=sin(45−30)=sin45.cos30−sin30.cos45
sin75=sin(30+45)=sin30.cos45+sin45.cos30sin75=sin(30+45)=sin30.cos45+sin45.cos30

sin15=sin(45−30)=sin45.cos30−sin30.cos45=2–√2.3–√2−12.2–√2=6–√−2–√4sin15=sin(45−30)=sin45.cos30−sin30.cos45=22.32−12.22=6−24

sin75=sin(30+45)=sin30.cos45+sin45.cos30=12.2–√2+2–√2.3–√2=2–√+6–√4sin75=sin(30+45)=sin30.cos45+sin45.cos30=12.22+22.32=2+64

sin15+sin75=6–√−2–√4+2–√+6–√4=26–√4=6–√2sin15+sin75=6−24+2+64=264=62