7sinxcosx+9cosx=0

Question

math

Answer 1

x= pi/2 + 2pi*n, x = 3pi/2 + 2pi*n <----------- solution

Answer 2

Solve by factoring.

cosx(7sinx+9) = 0

Set each factor equal to zero (zero product property_.

cos x = 0 or 7sinx + 9 = 0

For cos x = 0:

x = cos^-1(0)

x = π/2 + kπ, k is any integer

For 7sinx + 9 = 0:

7sinx = -9

sinx = -9/7

x = sin^-1(-9/7)

The solution set for this factor is empty set since there are no angles that have a sine of -9/7.

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