How do I use Pascal's triangle to expand a binomial?
1 Answer
Oct 31, 2015
Rows of Pascal's triangle provide the coefficients to expand
Explanation:
To expand
For example,
How about
Let
Then:
#(2x-5)^4 = (a+b)^4 = a^4+4a^3b+6a^2b^2+4ab^3+b^4#
#=(2x)^4+4(2x)^3(-5)+6(2x)^2(-5)^2+4(2x)(-5)^3+(-5)^4#
#=16x^4+4(8x^3)(-5)+6(4x^2)(25)+4(2x)(-125)+(625)#
#=16x^4-160x^3+600x^2-1000x+625#