Question

USING MATLAB

please show all commands

(sin x + cos x)^2 = 1 + 2sin xcos x (b) 1 - 2cos x - 3cos^2 x/sin^2 x = 1 - 3cos x/1 - cos x For each part, verify that the identity is correct by calculating the values of the left and right sides of the equation, substituting x=20 degree.

Answer 1

fprintf('\nChecking first identity: \n');
x = 20;
LHS = (sind(x) + cosd(x)).^2;
RHS = 1+(2*(sind(x)*cosd(x)));
if (abs(LHS-RHS) <= 0.001)
   fprintf('Identity is correct.\n');
else
   fprintf('Identity is incorrect.\n');
end

fprintf('\nChecking second identity: \n');
LHS = (1-(2*cosd(x)-3*(cosd(x).^2)))/(sind(x).^2);
RHS = (1-(3*cosd(x)))/(1-cosd(x));
if (abs(LHS-RHS) <= 0.001)
   fprintf('Identity is correct.\n');
else
   fprintf('Identity is incorrect.\n');
end