Помогите разобрать ошибки!

#include
#include
int main() {
double a=4.2, b=5.3, x, y, z;
x=a-(b*(a*log10));
y=(pow((sin*a),2))+(b*cos*x);
if (x>=0)
z=log(fabs(b*x+y));
else
z=x+(y/a);
printf("x = %lf\t y = %lf z = %lf\n", x, y, z);
getchar();
return 0; }
Выдает ошибки:

\Untitled1.c||In function 'main':|
\Untitled1.c|5|error: invalid operands to binary * (have 'double' and 'double (*)(double)')|
\Untitled1.c|6|error: invalid operands to binary * (have 'const double (*)(double)' and 'double')|
\Untitled1.c|6|error: invalid operands to binary * (have 'double' and 'const double (*)(double)')|
||=== Build finished: 3 errors, 0 warnings ===|