Question

4cos square theta -3sin square theta+2

Answer 1

$4cos {}^{2} \ \alpha - 3 \sin {}^{2} \alpha + 2 \\ 4cos {}^{2} \alpha - 3(1 - \cos {}^{2} \alpha ) + 2 \\ 4cos {}^{2} \alpha - 3 + 3 \cos {}^{2} \alpha + 2 \\ 7 \cos {}^{2} \alpha - 1$

Answer 2

4cos²@-3sin²@+2=4(1-sin²@)-3sin²@+2
=4-4sin²@-3sin²@+2
=-7sin²@+6=0
7sin²@=6
sin²@=6/7
sin@=√6/7
cos@=√1-sin²@=√1-(√6/7)²=√1-6/7=√1/7