就是这个样的粗爆，手搓一个计算器：半角计算器

线上运行，可以直接打开：半角计算器(在线计算器)

       作为程序员，没有合适的工具，就得手搓一个，PC端，移动端均可适用。废话不多说，直接上代码。

HTML:

<div class="calculator"><label for="angle">输入角度（度）：</label> <input id="angle" step="0.01" type="number" placeholder="输入角度"> <label for="formula">选择公式：</label><select id="formula"><option value="sin_half">sin(θ/2) = ±√((1 - cos(θ)) / 2)</option><option value="cos_half">cos(θ/2) = ±√((1 + cos(θ)) / 2)</option><option value="tan_half">tan(θ/2) = ±√((1 - cos(θ)) / (1 + cos(θ)))</option></select><button onclick="calculateHalfAngle()">计算</button><div id="result" class="result">结果将显示在这里</div></div>

JS:

function calculateHalfAngle() {
        const angle = parseFloat(document.getElementById('angle').value);
        const formula = document.getElementById('formula').value;
        
        if (isNaN(angle)) {
            document.getElementById('result').textContent = "请输入有效的角度值。";
            return;
        }

        // 将角度转换为弧度
        const radians = angle * (Math.PI / 180);
        const cosTheta = Math.cos(radians);

        let result;

        switch (formula) {
            case 'sin_half':
                result = Math.sqrt((1 - cosTheta) / 2);
                document.getElementById('result').textContent = `sin(${angle}°/2) 的结果是：${result.toFixed(4)}`;
                break;
            case 'cos_half':
                result = Math.sqrt((1 + cosTheta) / 2);
                document.getElementById('result').textContent = `cos(${angle}°/2) 的结果是：${result.toFixed(4)}`;
                break;
            case 'tan_half':
                result = Math.sqrt((1 - cosTheta) / (1 + cosTheta));
                document.getElementById('result').textContent = `tan(${angle}°/2) 的结果是：${result.toFixed(4)}`;
                break;
            default:
                document.getElementById('result').textContent = "请选择有效的公式。";
                break;
        }
    }

 CSS:

.calculator {
    width: 100%;
    background-color: #333;
    color: white;
    padding: 20px;
    border-radius: 10px;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.3);
}


label {
    display: block;
    margin-bottom: 10px;
    font-size: 16px;
}

input, select {
    width: 100%!important;
    padding: 10px!important;
    margin-bottom: 20px;
       color: #000000; 
    border-radius: 5px;
    border: 1px solid #555;
    font-size: 16px!important;
    background-color: #ffffff!important;
}

button {
    width: 100%;
    padding: 10px;
    background-color: #007bff;
    color: white;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    font-size: 16px;
}

button:hover {
    background-color: orange;
}

.result {
  font-size: 18px;
    margin-top: 20px;
    text-align: center;
}

option {
        background-color: #ffffff;
}


p {
    font-size: 18px;
        margin-top: 5px!important;
}