Question

В треугольнике BCD, BC=5,CD=4^2, а угол BDC=45 градусов. Найти sin CBD.

Answer 1

Дано: треугольник BCD

         BC=5

         CD=4^2=16

         <BDC=45

Найти: sinCBD

Решение:

По теореме синусов:

$frac{BC}{sinBDC}=frac{CD}{sinCBD}$</var></p> <p><img src=[/tex]frac{5}{sqrt{2}/2}" title="frac{BC}{sinBDC}=frac{CD}{sinCBD}" title="frac{5}{sqrt{2}/2}" title="frac{BC}{sinBDC}=frac{CD}{sinCBD}" alt="frac{5}{sqrt{2}/2}" title="frac{BC}{sinBDC}=frac{CD}{sinCBD}" />

$frac{BC}{sinBDC}=frac{CD}{sinCBD}$

$<var>frac{5}{sqrt{2}/2}$= $frac{16}{sinCBD}" title="<var>frac{5}{sqrt{2}/2}" />= [tex]frac{16}{sinCBD}" alt="<var>frac{5}{sqrt{2}/2}" />= [tex]frac{16}{sinCBD}" /></var></var></p> <p>[tex]sinCBD$= $frac{5sqrt{2}}{16}$