a、b、c、是三角形ABC三边,a、b、c、满足等式:b的平方=(c+a)(c-a),且5b-4c=0.求sinA+sinB的值

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a、b、c、是三角形ABC三边,a、b、c、满足等式:b的平方=(c+a)(c-a),且5b-4c=0.求sinA+sinB的值a、b、c、是三角形ABC三边,a、b、c、满足等式:b的平方=(c+a

a、b、c、是三角形ABC三边,a、b、c、满足等式:b的平方=(c+a)(c-a),且5b-4c=0.求sinA+sinB的值
a、b、c、是三角形ABC三边,a、b、c、满足等式:b的平方=(c+a)(c-a),且5b-4c=0.求sinA+sinB的值

a、b、c、是三角形ABC三边,a、b、c、满足等式:b的平方=(c+a)(c-a),且5b-4c=0.求sinA+sinB的值
b的平方=(c+a)(c-a)=c^2-a^2 即c^2=a^2+b^2 ∴∠C=90°
又5b-4c=0 5b=4c b:c=4:5=sinB ∴ a:c=3:5=sinA
∴sinA+sinB=7:5

Because of the Christmas, the whole December were dyed profusion party season, the bells tolled, yet he growled carnival heat wave came. In the dance full of heat, champagne, people put beside the hea...

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Because of the Christmas, the whole December were dyed profusion party season, the bells tolled, yet he growled carnival heat wave came. In the dance full of heat, champagne, people put beside the heavy midwinter to toss clouds, calinton stream will be frivolous, shine, mini dress called to him. However, dressed casually BoLou is not easily become carnival through can focus. This one season, party animal in the "golden benchmarking will tacky" with the spring color bead piece, simple outline model with pink color, unexpectedly reveals how much tong qu, Proud queen with filar satin social choice with noble purple, fashionable tassel also jumped into their largely untouched by static also move, also, keep low-key missish, elegant have an eyelid. Princess skirt, scoop-back outfit, exaggerated glaring adorn article, the usual bestow favor on the leading role, supporting by burnish hind also in succession, a new play for dazzing female people of shaping different sides,true religion billy, also for this wonderful carnival season official blew countdown horn.
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