cos²a=1-sin²=1-(8/17)²=1-64/289=225/289
cosa=√225/289=15/17
ctga=cosa/sina=8/17:15/17=8/17*17/15=8/15
cos²a=1-sin²=1-(8/17)²=1-64/289=225/289
cosa=√225/289=15/17
ctga=cosa/sina=8/17:15/17=8/17*17/15=8/15