Question

why sin(90+x) is cos x ....show me geometrically...please....ᴄʟᴀꜱꜱ 11 ᴍᴀᴛʜꜱ ​

Answer 1

Good morning

Compound Bow

$sin(x+y)=sinx.cosy+cosx.siny$

$\mathrm{Problem}:$

$sin(90+x)=sin90.cosx+cos90.senx$

$\mathrm{But}$

$sin90=1 \ \ \ and \ \ \ cos90=0$

$\mathrm{Replacing}$

$sin(90+x)=1.cosx+0.senx$

$sin(90+x)=cosx+0$

$sin(90+x)=cosx$

good bye.