Find the sum `"^(19)C_3`+ `"^(19)C_5` + `"^(19)C_7` + ….+`"^(19)C_(19)`

Find the sum (-7)/(19) + (-3)/(38)

Find the sum: -8/19 + (-2)/57

The sum S = ""^(20)C_(2) + 2*""^(20)C_(3) + 3 *""^(20)C_(4) + ...+ 19 * ""^(20)C_(20) is equal to

The value of sum_(r=0)^(20)r(20-r)(^(20)C_r)^2 is equal to 400^(39)C_(20) b. 400^(40)C_(19) c. 400^(39)C_(19) d. 400^(38)C_(20)

Find the value of [i^19+(1/i)^25]^2

Find the value of : -19-(-16)

Find the value of : tan frac (19 pi)(3) .

Evaluate the following : "^19C_17+ ^19C_18 .

Find the sum of the following : -8/19 + -2/57