The number of terms with integral coefficients in the expansion of…

The number of terms with integral coefficients in the expansion of \(\Big(17^{\frac{1}{3}}+35^{\frac{1}{2}}\text{x}\Big)^{600}\) is:

  1. 100

  2. 101

  3. 150

  4. 50

Solution

Solution:

The general term Tr+1 in the given expansion is given by \({^\text{600}}\text{C}_{\text{r}}(17^{\frac{1}{3}})^{600-\text{r}}\Big(35^{\frac{1}{2}}\text{x}\Big)^{\text{r}}\)

\(={^\text{600}}\text{C}_{\text{r}}(17^{\frac{1}{3}})^{200-\frac{\text{r}}{3}}\times\Big(35^{\frac{\text{r}}{2}}\text{x}\Big)^{\text{r}}\)

Now, Tr+1 is an integer if \(\frac{\text{r}}{2}\) and \(\frac{\text{r}}{2}\) are integers for all \(0\leq\text{r}\leq600\)

Thus, we have

r = 0, 6, 12, ....600

Since, It is an A.P

So, \(600 = 0 + (\text{n} - 1)6\)

\(\Rightarrow \text{n}=101\)

Hence, there are 101 terms with integral coefficients.

Asked in: RDSHARMA

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