Question

x=cos20-sin20,then ..
a) x>0 b) x<0 c) x=0 d) none​

Answer 1

Step-by-step explanation:

cos y = sin(90-y) using this transformation

cos 20= sin (90-20)

cos20= sin70

x= sin 70-sin 20 both lie in first quadrant and in this quad sin is an increasing I.e. as angle increases its sin value increases .

so, sin70>sin20

sin 70-sin 20>0

so x>0