Question

Find the value of k, if x=-2,y=1 is a solution of the equation 5x+3y=k​

Answer 1

Answer:

Since 18o corresponds to π10 we can write (using de Moivre formula):

(cosπ10+isinπ10)5=cos5π10+isin5π10=i.

Let’s put cosπ10=x and sinπ10=y and use the binomial expansion of the left hand side

∑5k=0xk(iy)5−k=iy5+5xy4–10ix2y3–10x3y2+5ix4y+x5=i.

Step-by-step explanation:

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Answer 2

Answer:

The value of x = -2 and y = 1....

Putting it in the equation.....

5x + 3y = k

5 (-2) + 3 (1) = k

-10 + 3 = k

k = -7.....

Here's your required answer........

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