Answer:
15x^2
Step-by-step explanation:
By looking the given options, we can say that some of them are following pythagorean identities and pythagorean identities are
sin^2(x) + cos^2(x) =1, sec^2(x)-tan^2(x) =1,csc^2(x) -cot^2(x)=1
So out the four options, option a and option c are following pythagorean identity and option b and option d are not following pythagorean identity. And we have to find those options which are not identities .
So the correct options are
b) sec^{2} x+csc^{2} x=1 \ d) tan^{2} x + sec^{2} x =1
Direct variation is of the form y=kx. We are given the point (8, -4) so we can solve for k, the constant of variation...
-4=8k, divide both sides by 8
-4/8=k
k=-0.5, so our equation is:
y=-0.5x,