Write the product as a sum.
9cos(6x) cos(9x)

9/2 [ cos(15x) + cos(3x) ]

Step-by-step explanation:

9cos(6x) . cos(9x) can be expressed as

= 9/2 * 2cos (6x) * cos(9x)  next  here we will apply the rule

2cosA . cosB = cos(A+B)  + cos( A-B)

where A = 6x , B = 9x

hence : 9cos(6x) . cos(9x)  expressed as a sum will be

= 9/2 * [cos( 6x+ 9x) + cos( 6x - 9x ) ]

= 9/2 [ cos (15x ) + cos(-3x) ]

the final sum = 9/2 [ cos(15x) + cos(3x) ]

v = 1/3 a^2h

step-by-step explanation:

if the height is 57.7cm and the height of the slant edge is 18.2cm, then the volume is 1/3 a^2h.