cannot find symbol mathhelper.cos

i have a mob and it used to be fine but i made a new model for it but now i am getting error: cannot find symbol and it shows the arrow is above Mathhelper.cos

this is the where the error was its in the renderer of the mob: 

package net.mcreator.newblocks.entity.renderer;

import net.minecraftforge.fml.client.registry.RenderingRegistry;
import net.minecraftforge.eventbus.api.SubscribeEvent;
import net.minecraftforge.client.event.ModelRegistryEvent;
import net.minecraftforge.api.distmarker.OnlyIn;
import net.minecraftforge.api.distmarker.Dist;

import net.minecraft.util.ResourceLocation;
import net.minecraft.entity.Entity;
import net.minecraft.client.renderer.texture.OverlayTexture;
import net.minecraft.client.renderer.model.ModelRenderer;
import net.minecraft.client.renderer.entity.model.EntityModel;
import net.minecraft.client.renderer.entity.layers.LayerRenderer;
import net.minecraft.client.renderer.entity.MobRenderer;
import net.minecraft.client.renderer.entity.IEntityRenderer;
import net.minecraft.client.renderer.RenderType;
import net.minecraft.client.renderer.IRenderTypeBuffer;

import net.mcreator.newblocks.entity.WardenEntity;

import com.mojang.blaze3d.vertex.IVertexBuilder;
import com.mojang.blaze3d.matrix.MatrixStack;

@OnlyIn(Dist.CLIENT)
public class WardenRenderer {
    public static class ModelRegisterHandler {
        @SubscribeEvent
        @OnlyIn(Dist.CLIENT)
        public void registerModels(ModelRegistryEvent event) {
            RenderingRegistry.registerEntityRenderingHandler(WardenEntity.entity, renderManager -> {
                return new MobRenderer(renderManager, new Modelwarden(), 1.4f) {
                    {
                        this.addLayer(new GlowingLayer<>(this));
                    }
                    @Override
                    public ResourceLocation getEntityTexture(Entity entity) {
                        return new ResourceLocation("new_blocks:textures/warden.png");
                    }
                };
            });
        }
    }

    @OnlyIn(Dist.CLIENT)
    private static class GlowingLayer<T extends Entity, M extends EntityModel<T>> extends LayerRenderer<T, M> {
        public GlowingLayer(IEntityRenderer<T, M> er) {
            super(er);
        }

        public void render(MatrixStack matrixStackIn, IRenderTypeBuffer bufferIn, int packedLightIn, T entitylivingbaseIn, float limbSwing,
                float limbSwingAmount, float partialTicks, float ageInTicks, float netHeadYaw, float headPitch) {
            IVertexBuilder ivertexbuilder = bufferIn.getBuffer(RenderType.getEyes(new ResourceLocation("new_blocks:textures/warden_glow.png")));
            this.getEntityModel().render(matrixStackIn, ivertexbuilder, 15728640, OverlayTexture.NO_OVERLAY, 1, 1, 1, 1);
        }
    }

    // Made with Blockbench 3.9.3
    // Exported for Minecraft version 1.15 - 1.16 with MCP mappings
    // Paste this class into your mod and generate all required imports
    public static class Modelwarden extends EntityModel<Entity> {
        private final ModelRenderer head;
        private final ModelRenderer left_ear_r1;
        private final ModelRenderer body;
        private final ModelRenderer body_r1;
        private final ModelRenderer right_arm;
        private final ModelRenderer left_arm;
        private final ModelRenderer left_leg;
        private final ModelRenderer right_leg;
        public Modelwarden() {
            textureWidth = 128;
            textureHeight = 64;
            head = new ModelRenderer(this);
            head.setRotationPoint(0.0F, -10.0F, 0.0F);
            setRotationAngle(head, 0.1745F, 0.0F, 0.0F);
            left_ear_r1 = new ModelRenderer(this);
            left_ear_r1.setRotationPoint(0.0F, 34.0F, 0.25F);
            head.addChild(left_ear_r1);
            setRotationAngle(left_ear_r1, 0.0401F, 0.0F, 0.0F);
            left_ear_r1.setTextureOffset(106, 46).addBox(8.0F, -53.0F, 0.0F, 10.0F, 10.0F, 0.0F, 0.0F, false);
            left_ear_r1.setTextureOffset(106, 36).addBox(-18.0F, -53.0F, 0.0F, 10.0F, 10.0F, 0.0F, 0.0F, false);
            left_ear_r1.setTextureOffset(0, 0).addBox(-8.0F, -50.0F, -5.0F, 16.0F, 16.0F, 10.0F, 0.0F, false);
            body = new ModelRenderer(this);
            body.setRotationPoint(0.0F, -10.0F, 0.0F);
            setRotationAngle(body, 0.1309F, 0.0F, 0.0F);
            body_r1 = new ModelRenderer(this);
            body_r1.setRotationPoint(0.0F, 11.0F, 0.0F);
            body.addChild(body_r1);
            setRotationAngle(body_r1, 0.0436F, 0.0F, 0.0F);
            body_r1.setTextureOffset(0, 26).addBox(-9.0F, -11.0219F, -6.0032F, 18.0F, 21.0F, 11.0F, 0.0F, false);
            right_arm = new ModelRenderer(this);
            right_arm.setRotationPoint(-11.0F, -6.0F, 0.0F);
            setRotationAngle(right_arm, -0.1309F, 0.0F, 0.0F);
            right_arm.setTextureOffset(52, 0).addBox(-6.0F, -4.0F, -4.0F, 8.0F, 28.0F, 8.0F, 0.0F, false);
            left_arm = new ModelRenderer(this);
            left_arm.setRotationPoint(11.0F, -6.0F, 0.0F);
            setRotationAngle(left_arm, -0.1309F, 0.0F, 0.0F);
            left_arm.setTextureOffset(84, 0).addBox(-2.0F, -4.0F, -4.0F, 8.0F, 28.0F, 8.0F, 0.0F, false);
            left_leg = new ModelRenderer(this);
            left_leg.setRotationPoint(6.0F, 11.0F, 0.0F);
            left_leg.setTextureOffset(82, 36).addBox(-3.0F, 0.0F, -2.5F, 6.0F, 13.0F, 6.0F, 0.0F, false);
            right_leg = new ModelRenderer(this);
            right_leg.setRotationPoint(-6.0F, 11.0F, 0.75F);
            right_leg.setTextureOffset(58, 36).addBox(-3.0F, 0.0F, -3.0F, 6.0F, 13.0F, 6.0F, 0.0F, false);
        }

        @Override
        public void render(MatrixStack matrixStack, IVertexBuilder buffer, int packedLight, int packedOverlay, float red, float green, float blue,
                float alpha) {
            head.render(matrixStack, buffer, packedLight, packedOverlay);
            body.render(matrixStack, buffer, packedLight, packedOverlay);
            right_arm.render(matrixStack, buffer, packedLight, packedOverlay);
            left_arm.render(matrixStack, buffer, packedLight, packedOverlay);
            left_leg.render(matrixStack, buffer, packedLight, packedOverlay);
            right_leg.render(matrixStack, buffer, packedLight, packedOverlay);
        }

        public void setRotationAngle(ModelRenderer modelRenderer, float x, float y, float z) {
            modelRenderer.rotateAngleX = x;
            modelRenderer.rotateAngleY = y;
            modelRenderer.rotateAngleZ = z;
        }

        public void setRotationAngles(Entity e, float f, float f1, float f2, float f3, float f4) {
            this.head.rotateAngleY = f3 / (160F / (float) Math.PI);
            this.head.rotateAngleX = f4 / (164F / (float) Math.PI);
            this.right_arm.rotateAngleX = MathHelper.cos(f * 0.6662F + (float) Math.PI) * f1;
            this.left_leg.rotateAngleX = MathHelper.cos(f * 1.0F) * -1.0F * f1;
            this.left_arm.rotateAngleX = MathHelper.cos(f * 0.6662F) * f1;
            this.right_leg.rotateAngleX = MathHelper.cos(f * 1.0F) * 1.0F * f1;
            this.body_r1.rotateAngleX = MathHelper.cos(f * 0.1F) * 0.2F * f1;
            this.body_r1.rotateAngleZ = MathHelper.cos(f * 0.1F) * 0.1F * f1;
            this.right_leg.rotateAngleZ = MathHelper.cos(f * 0.1F) * 0.2F * f1;
            this.left_leg.rotateAngleZ = MathHelper.cos(f * 0.1F) * 0.2F * f1;
            this.left_arm.rotateAngleZ = MathHelper.cos(f * 0.1F) * 0.1F * f1;
            this.right_arm.rotateAngleZ = MathHelper.cos(f * 0.1F) * 0.1F * f1;
            this.head.rotateAngleX = MathHelper.cos(f * 0.2F) * 0.2F * f1;
            this.head.rotateAngleZ = MathHelper.cos(f * 0.2F) * 0.3F * f1;
            this.head.rotateAngleY = MathHelper.cos(f * 0.3F) * 0.2F * f1;
        }
    }
}