Basic Mathematics

Inverse trigonometry

Question:
A boy can make 3 dolls in 4 days. In how many days will he take to prepare 12 dolls?
Solution:
As, work and days are directly proportional (more work take more days)
Work (doll)3÷Work (doll)12
=days(4)÷
days(X)
Dolls (3/12)
=days (4/X)
3x=12×4
X=(12×4)/3
X=4×4=16
Answer: 16days

Find
d/dx
_/{(1+Cos2x)/(1-Cos2x)}