一道英文数学题目(追加10分)
Inpriatesofthecaribbean,acannonwasfiredatanenemyship.Themuzzlevelocitywas60m/s.Atwhatangleabovethehorizontalmustthecannonhavebeenaimedinordertohittheenemyship320maway?(Dontworryaboutintialheightonthisone.Theshipswillbeatthesamelevelduetocalmseas)
我用算式y=-4.9t^2+60sin(theta)t和x=60cos(theta)t然后设320=60cos(theta)t然后我知道要用sintheta/costheta但是怎么做呢?