If, 
show that 
Given, 
Taking logarithm both sides, we get
⇒ log y = a cos – 1x log e
⇒ log y = a cos – 1x [log e = 1]
Differentiating both sides with respect to x
⇒ 
Squaring both sides
⇒ 
Differentiating both sides
⇒ 
⇒ 
⇒ 
∴ 
Hence, proved
23
If, show that
Given,
Taking logarithm both sides, we get
⇒ log y = a cos – 1x log e
⇒ log y = a cos – 1x [log e = 1]
Differentiating both sides with respect to x
⇒
Squaring both sides
⇒
Differentiating both sides
⇒
⇒
⇒
∴
Hence, proved