The equation is given by:
Let the number be denoted by x.
Now, we are given a word phrase as follows:
One-third of a number less than nine is equal to seven.
Now this word phrase could be mathematically expressed as a equation by:
one-third of x is: 1/3 x
and this number less than 9 is given by:
Now, this number is equal to 7.
i.e. we finally have:
Answer:
sin/4 * sin
/6 = 1/2 *(cos
/12 - cos 5
/12)
Step-by-step explanation:
Formula:- sinX sinY = (1/2) [ cos (X - Y) - cos (X + Y) ]
sin(π/4)sin(π/6)
= (1/2)[cos(π/4 - π/6) - cos(π/4 + π/6)]
= (1/2)[cos(3π/12 - 2π/12) - cos(3π/12 + 2π/12)]
= (1/2)[cos(π/12) - cos(5π/12)]
