Question

已知cosα=2sinα,求角α的六个三角函数值!(请写出过程,写公式就好,计算过程可免)

Answer 1

tanα=sinα/cosα=sinα/2sinα=1/2

ctgα=1/tanα=1/(1/2)=2

sec²α=tan²α+1=(1/2)²+1=1/4+1=5/4

secα=±√5/2

cosα=1/secα=1/(±√5/2)=±2/√5=±2√5/5

sin²α=1-cos²α=1-(4/5)=1/5

sinα=±√5/5

cscα=1/sinα=±√5