1. ## terms and others

(2x^2 - 3/x)^18

how can I find the 16th term and follow up by finding the term that is independent of x?

2. Originally Posted by Stuart
(2x^2 - 3/x)^18

how can I find the 16th term and follow up by finding the term that is independent of x?
The 16th term of $(a+b)^{18}$ is,
${18 \choose 15}a^{15}b^3$
Over here $a=2x^2,b=-3/x$
Thus,
${18 \choose 15}(2x^2)^{15}(-3/x)^3=-816(2^{15}x^{30})\cdot \frac{3^3}{x^3}=-815\cdot 2^{15} \cdot 3^3\cdot x^{27}$

3. Ok well I am sure that K = 12 and N = 18

so to set it up is 18c12 * (2x^2)^18-12 * (-3/x)^12

Right and follow through with that you gave for the 16th term? If not what does the 18 over 15 mean?

4. Originally Posted by Stuart
Ok well I am sure that K = 12 and N = 18

so to set it up is 18c12 * (2x^2)^18-12 * (-3/x)^12

Right and follow through with that you gave for the 16th term? If not what does the 18 over 15 mean?
It is another way of writing 18C15