Question

7cos^2theta+3sin^2theta=4

Answer 1

7cos^2theta+3sin^2theta=4

>3+4cos^2theta=4

>4cos^theta=1

>cos^2theta=1/4

>cos(theta)=+1/2 or -1/2

>theta=cos^-1(1/2) or cos^-1(-1/2)

theta=pi/3 or 2pi/3