\(E=cos^220^0+cos^240^0+sin^2\left(90^0-50^0\right)+sin^2\left(90^0-70^0\right)\)
\(=cos^220^0+sin^220^0+cos^240^0+sin^240^0\)
\(=1+1=2\)
\(F=sin^211^0+sin^215^0+sin^232^0+cos^2\left(90^0-79^0\right)+cos^2\left(90^0-75^0\right)+cos^2\left(90^0-58^0\right)\)
\(=sin^211^0+cos^211^0+sin^215^0+cos^215^0+sin^232^0+cos^232^0\)
\(=1+1+1=3\)
\(C=\left(sin^2a+cos^2a\right)^3-3sin^2acos^2a\left(sin^2a+cos^2a\right)+3sin^2a.cos^2a\)
\(=1-3sin^2a.cos^2a.1+3sin^2a.cos^2a=1\)
\(E=\cos^220^0+\cos^240^0+\sin^240^0+\sin^220^0=1+1=2\\ F=\left(\sin^211^0+\sin^279^0\right)+\left(\sin^215^0+\sin^275^0\right)+\left(\sin^232^0+\sin^258^0\right)\\ F=\left(\sin^211^0+\cos^211^0\right)+\left(\sin^215^0+\cos^215^0\right)+\left(\sin^232^0+\cos^232^0\right)\\ F=1+1+1=3\\ C=\left(\sin^2a+\cos^2a\right)^3-3\sin^2a\cdot\cos^2a\left(\sin^2a+\cos^2a\right)^3+3\sin^2a\cdot\cos^2a\\ C=1-3\sin^2a\cdot\cos^2a+3\sin^2a\cdot\cos^2a=1\)
