manualintegrate.py 文件源码

def trig_product_rule(integral):
    integrand, symbol = integral

    sectan = sympy.sec(symbol) * sympy.tan(symbol)
    q = integrand / sectan

    if symbol not in q.free_symbols:
        rule = TrigRule('sec*tan', symbol, sectan, symbol)
        if q != 1 and rule:
            rule = ConstantTimesRule(q, sectan, rule, integrand, symbol)

        return rule

    csccot = -sympy.csc(symbol) * sympy.cot(symbol)
    q = integrand / csccot

    if symbol not in q.free_symbols:
        rule = TrigRule('csc*cot', symbol, csccot, symbol)
        if q != 1 and rule:
            rule = ConstantTimesRule(q, csccot, rule, integrand, symbol)

        return rule