Answer:
see explanation
Step-by-step explanation:
Using the identity
tan x = 
Consider the left side

=
( multiply numerator and denominator by cos²x to clear fractions
=
← ( cos²x + sin²x = 1 ]
= cos²x - sin²x
= right side , thus proven
Answer:
your father 47+y You x+y
Step-by-step explanation:
Your father is 47 + y years old after y years
You will be x + y years old after y years.
Twelth square number is the square of 11 that is 121 as 0 is the square of of 0. Than 1=1, 2=4, 3=9, 4=16, 5=25, 6=36, 7=49, 8=64, 9=81, 10=100.