Question

I really need help solving thisIt’s from my trig prep bookIt asks to answer (a) and (b)

Answer 1

Answer:

The sum in summation notation is:

`\sum ^4_{r\mathop{=}0}(-1)^r(4Crx^(4-r)y^r)`

The expansion is:

`81x^(20)-12x^(15)y^3+(2)/(3)x^(10)y^6-(4)/(243)x^5y^9+(1)/(6561)y^(12)`

Step-by-step explanation:

Given the expression:

`(3x^5-(1)/(9)x^3)^4`

In summation notation, this can be written as:

`\sum ^4_(r\mathop=0)(-1)^r(4Crx^(4-r)y^r)`

The simplified terms of the expression is: